OHSP

Big yikes, but in the interest of fairness, who said this? Was it a random faculty member/panelist/grad student or someone you would expect to mentor you or support your career directly?

I second Sigaba's comment. I know of a couple of star scholars who can place students well but are borderline emotionally abusive in different ways and make their advisees' grad school experience a living hell. It's important to know if that's the situation you're walking into so you can make an informed decision about the environment you'll be in for the next several years of your life.
That's one thing you need to know. The other is, as others have said, your potential advisor's placement record. I would include their dropout record here as well and ask for the reasons their former students who didn't graduate left the program. Often that happens because the student didn't feel grad school was for them, which is fine, but sometimes the advisor or department could play a role in pushing someone out of academia.
You want to know if your advisor has a track record of turning administrative formalities like renewal forms or evaluations that no one else in the department takes seriously into massive trials, if they refuse to let students defend for years on end, if they frequently clash with students over conceptual questions pertaining to their dissertations, if they are inaccessible or indifferent, if they are liable to forget who you are in between meetings, if they have ever messed up handling a student's medical/mental health/pregnancy/parenthood/family/academic issues, etc.
Frankly, it sounds like School B is a better fit, has more money for you and would make you happier, plus the warning that having a second advisor would be a good idea is a massive red flag re. School A. So I will give you different advice from some others and tell you that it's reasonable to lean toward School B at this point. If you were choosing between a mediocre advisor at a top-10 department and a great advisor at a top-30 department, assuming they were ranked by placement and not just by the USNWR's weird criteria, the latter would be harder to justify because of the massive placement advantage the former would be likely to have. But, frankly, both of your choices probably have a hard time competing for plum jobs/postdocs with top departments, so the difference in ranking is less significant.
Again, as everyone else has said, do look at your advisors' placement record first, in particular in recent years.

Attended Nova's Admitted Students Day and couldn't be happier with my choice!

To me, the key question is this. Is being in an environment that puts you in the best situation to get you what you need (a positive relationship with an advisor) less or more important than being in an environment that gets you what you want? (To be clear, I'm defining OP's need within a specific context, I'm not making any generalizations about others' needs or wants.)
MOO, you haven't presented enough information to indicate that you've done your due diligence on your most important criterion: the need for an advisor with whom you can establish meaningful rapport.
I recommend that, in addition to the guidance you've received so far, you reach out to former graduate students of professors you would work with at School A. Pie in the sky, you'd find a mix of former students that have secured the kinds of jobs you want and some who have not.
I emphasize former graduate students because, as you may have learned from your unfortunate experience, it can be exceptionally difficult to say to others that a bad situation is actually horrible when one is in the middle of it.

All of the advice above is really good -- I have a slightly different take... feel free to PM. 

Unless either of these institutions is truly renowned in your field (e.g., MSU for African history or Georgetown for Mideast history, which are really rare examples), look at your prospective advisors' placement records. If neither have placed many students, compare funding and research resources.

Okay, I went through and thought about everything in this thread, all of which I'm very appreciative for. My apologies for being short and frankly rude earlier; my mental health hasn't been in the best spot, obviously.
My concentration for my MA is definitely going to be European history, and I'm going to be taken a course on Medieval history (the focus is going to be largely social and cultural, including intersections of race/ethnicity, gender, and global encounters in Medieval England, France, and Iberia) in addition to my required Theory and Methods course. Since I want to apply to a PhD program again after getting my Masters, I will likely take @WhaleshipEssex's advice and produce research during the spring/summer while reading more, though I plan on continuing reading through next fall, obviously! I may take the research project from the Medieval history course and refine it. I'm temporally most interested in the High to Late Medieval period, into the Renaissance, in urban areas of England and north and central Italy. I'm going to use the rest of this semester and the summer to really come up with questions that I'm interested in, since I'm sure my current questions of what was life really like and are the preconceived notions that we have about the Medieval period really correct are a bit too broad.
Regarding language, I'll be taking an intensive Latin course over the summer (as well as referring to the Latin course by the National Archives of the UK, which is specifically Medieval Latin) and will also be working on French and German. 
 
 

Short answer: no.
Long answer: If you did not apply to any other MA programs, I'd take the year off.  I'd work on your languages and demonstrate them in your writing sample.  I'd apply to MA programs that have more funding and (ideally) in a cheaper area than NYC and PhD programs again and go from there.  With the economy being what it is, it's not worth taking out that much in loans.  It's also NOT worth staying in "deferment" for loans while in a PhD program as the interest still accrues.

No, don't do it.

My guess is that your top-choice program doesn't have the funds for "visiting weekends" as mentioned in these forums.  You can politely inquire about a prospective student day to the DGS and see what s/he says. 

Basically don't take it as anything yet, people are still making decisions about their offers, you might just be waiting on someone to officially turn down their place. I don't think waitlisted students are usually invited to prospective students days--the waiting part is tough but it'll end soon!

Basically don't take it as anything yet, people are still making decisions about their offers, you might just be waiting on someone to officially turn down their place. I don't think waitlisted students are usually invited to prospective students days--the waiting part is tough but it'll end soon!

Stick to your gut. These kinds of decisions are similar to weighing marriage proposals.  You just have to pick one partner to be with for the next 5-7 years. Have you talked with graduate students?  They can help you for sure; ask the Director of Graduate Studies and your POIs to connect with international students in your program.  These students can give you a real clarity on the process from accepting an offer to logistics of moving to the US to navigating the University's bureaucracy. 

From what I've seen, spring admission doesn't really exist in history PhD programs. 

I'm actually not entirely sure but I would ask if you can be put in touch with current MA students, who will have a better idea. Just from the website there's this (below)--that might be how students are funding themselves--though the website does seem a little incorrect to me (even with an MA we're all funded for 5 years for the phd, for instance). 
"The Graduate School’s Tuition Incentive Program (TIP) encourages students to apply for external grants and provides matching tuition points (from 50 to 100 percent) to eligible recipients of external awards from recognized, academic sources of funding outside NYU.  For applications and specific details about TIP eligibility criteria, please visitwww.nyu.edu/gsas/Admissions/tipform.html.  New York University offers several loan programs to students.  Information is available at www.nyu.edu/financial.aid or at the Office of Financial Aid, 212-998-4444. 
The GSAS/CAS Tuition Program: Qualified CAS students graduating in 2009 or later who complete the admissions application process and are admitted to the master's programs in History (World History, Archives and Public History, or History of Women and Gender), as well as the BA/MA program, in the term immediately following the year of their graduation from CAS, will be eligible to receive a 25% tuition discount for courses required for the degree program."

What would be the costs? Can't quite tell if you're saying that it'd be tuition free. If you don't have to pay tuition and thus don't have to go into huge debt, William and Mary is a great school that's likely to prepare you well for phd applications. 

Thanks for that information! Based on this it seems like it's a lot of work to get funding for their MA, and considering I have a funded MA offer already (should nothing positive happen with the 2 schools I'm waiting on plus 1 on the wait list for PhD) I'll probably turn down the NYU offer. I really appreciate your input though!

I'm actually not entirely sure but I would ask if you can be put in touch with current MA students, who will have a better idea. Just from the website there's this (below)--that might be how students are funding themselves--though the website does seem a little incorrect to me (even with an MA we're all funded for 5 years for the phd, for instance). 
"The Graduate School’s Tuition Incentive Program (TIP) encourages students to apply for external grants and provides matching tuition points (from 50 to 100 percent) to eligible recipients of external awards from recognized, academic sources of funding outside NYU.  For applications and specific details about TIP eligibility criteria, please visitwww.nyu.edu/gsas/Admissions/tipform.html.  New York University offers several loan programs to students.  Information is available at www.nyu.edu/financial.aid or at the Office of Financial Aid, 212-998-4444. 
The GSAS/CAS Tuition Program: Qualified CAS students graduating in 2009 or later who complete the admissions application process and are admitted to the master's programs in History (World History, Archives and Public History, or History of Women and Gender), as well as the BA/MA program, in the term immediately following the year of their graduation from CAS, will be eligible to receive a 25% tuition discount for courses required for the degree program."

No--I honestly think it's a good idea to take a year (or more) away from academia (even if you've already taken time off between undergrad and the MA). Keep up with scholarly conversations, keep thinking about your own research interests, maybe start looking through some comprehensive exam lists (some schools have lists posted online--I'd highly recommend the lists up on the Wisconsin Madison site), etc, but for your own sanity time off can be a good thing. I also found that after time off I was like, yeahhhh I'm ready to go back now. 

And even with a master's degree or master's degrees, PhD students in US programs sometimes still need to do the course work and get another MA (then a MPhil) on their way towards passing the comprehensive exam, which will make me a serial Master's degree collector...
Also, while schools may not care that much about your course load, some (great) programs do care about the kind of courses you've taken. When I was applying for the first time (spoiler alert: I didn't succeed), one of the reasons for my top program to reject me was that I didn't take any courses related to pre-20th century Japanese history (my focus was 20th century Japanese history back then). 

Controversial statement but US PhD programs are just rigorous in a very different way. I think people outside of the US, unfamiliar with the US system, assume that the two years of coursework are "unnecessary", time-wasting, etc (these are opinions I encountered when I was writing my MA outside of the US). Coursework years are better considered as focused reading years that both compel you and provide you with time to establish breadth of knowledge, to diversify research interests, and to work towards your project with faculty you might not otherwise encounter (and who often have thoughtful advice to offer re your work). Sometimes I've hated the coursework, but it's already made the dissertation I'm working towards so much better. Being in the US has made me even more skeptical of 3 to 4 year PhD programs--it's enough time to write a focused dissertation on a specialized subject, but I don't think it's enough time to become truly well-versed in literature across multiple fields. I'm really glad I didn't enter a program that would have had me writing my dissertation proposal and dissertation (and little else) right away--which isn't to say that I won't use the writing I've worked on in coursework years. US departments know about these differences, and so Oxbridge prestige doesn't mean all that much. 

Controversial statement but US PhD programs are just rigorous in a very different way. I think people outside of the US, unfamiliar with the US system, assume that the two years of coursework are "unnecessary", time-wasting, etc (these are opinions I encountered when I was writing my MA outside of the US). Coursework years are better considered as focused reading years that both compel you and provide you with time to establish breadth of knowledge, to diversify research interests, and to work towards your project with faculty you might not otherwise encounter (and who often have thoughtful advice to offer re your work). Sometimes I've hated the coursework, but it's already made the dissertation I'm working towards so much better. Being in the US has made me even more skeptical of 3 to 4 year PhD programs--it's enough time to write a focused dissertation on a specialized subject, but I don't think it's enough time to become truly well-versed in literature across multiple fields. I'm really glad I didn't enter a program that would have had me writing my dissertation proposal and dissertation (and little else) right away--which isn't to say that I won't use the writing I've worked on in coursework years. US departments know about these differences, and so Oxbridge prestige doesn't mean all that much. 

No--I honestly think it's a good idea to take a year (or more) away from academia (even if you've already taken time off between undergrad and the MA). Keep up with scholarly conversations, keep thinking about your own research interests, maybe start looking through some comprehensive exam lists (some schools have lists posted online--I'd highly recommend the lists up on the Wisconsin Madison site), etc, but for your own sanity time off can be a good thing. I also found that after time off I was like, yeahhhh I'm ready to go back now. 

After a stressful application season, yesterday I found out I was accepted at UT Austin! As a Latin Americanist, I am ecstatic and just wanted to thank you all for your advice/encouragement throughout the process. 

Don’t discount Penn yet, though. Some people will be trying to make a decision about schools right up until the April 15 deadline. I’m amongst the terrible people who’ve turned down offers on April 15 (and I know that, at Penn, when I turned down my offer someone else was offered a spot in my place). Ie if you’d prefer Penn over Temple, wait it out for a while, even though it’s painful, because you don’t want to be in a position where you accept Temple then get into Penn etc etc—it just becomes a mess. 
Also, to people weighing multiple offers, try to turn down offers you know you’re not going to accept as soon as you can. If you’re tossing up between two schools even after visit days, get in contact with as many relevant people as you can—grad students, potential committee members etc.