Current 2nd year PhD student at a flagship Midwest school here. This time a couple years ago, I was deciding between 4 fully funded PhD program offers and even though each of them would have been great places to attend, I basically have never regretted my decision to choose the school I'm at now. To be honest, one of the main reasons I ended up choosing the school i I did and I think a really important factor to take into consideration (if your programs are all pretty much ranked the same, which mine were — ranked around 20 on the US News Report, whatever that's worth and all generally strong in 20th/21st century American which is what I do) is money. By that I mean, of course, how much your yearly stipend would be and how much that actually is when you factor in cost of living. I chose a stipend where I don't really have to watch every single penny and dime I spend. I am actually managing to save money for retirement, which I would have never been able to do with another offer I received from a more urban school with a much higher cost of living. A lot of the grad students I spoke to at the more urban school had to take out second jobs and live with roommates to make their stipend stretch further. Of course, there is nothing wrong with living with roommates for some people and I actually do right but I think the crucial thing is that I have the financial option to live alone if I ever wanted to. I love the flexibility that my more livable stipend affords me — I can go out for drinks and dinner with cohort mates and not stress if it's going to ruin my budget; I can pay for a flight for a conference and still pay rent while I wait for the reimbursement to come through.
And that brings me to another reason why I think money is so important — I think it's important to suss out how much money departments have for things like conference funding, fellowships, summer support, etc. Again, at the more urban school I was considering, I spoke to grad students who told me the max funding they got for conferences was $300. At my current school, you get a minimum of $300 for domestic conference travel. Most students there also began teaching their first year; while this might be unavoidable depending on the offers you have, if you have any offers that allow you to be on fellowship your first year, I would seriously consider those. Everyone in my program is on fellowship their first year, which gives you some time to get adjusted to grad school without teaching responsibilities and also allows you to knock a lot of coursework out in your first year. While I do enjoy teaching now, having that first year to just focus on adjusting to grad seminars and life in a new city was immensely valuable. I don't want to harp too much on the money because obviously we're not in this field to get rich but not having to stress so much about money has been great for my mental health and quality of living.
One last thing (this probably applies more to people coming straight out of undergrad, like I was, but may apply to those with an MA too): your research interests might change and it's good to suss out if there's several people in the department you might work well with. For example, I applied to the school I'm currently at to work with one superstar professor in my specific field. But my research interests have shifted as I've taken more coursework and while I'm still interested in my initial field, my theoretical investments have shifted so that the professor I applied to work with probably won't even end up on my prelims committee. Of course, you can't predict how your interests might shift but when I was visiting programs, my undergrad advisors told me to make sure there were several people I could see myself working with, just in case a professor leaves or your interests do shift. I was quite sure that I would stay a 20th/21st century Americanist throughout (and still am!) but I made a point during visit days to connect with several other Americanists in the department besides my POI. I'm glad I did because that meant I didn't freak out when my interests began to change and was confident that there were enough Americanists in the department that I could form a solid prelims committee.
Relatedly, when thinking about advisors, someone's specific research interests matter less than you might think. Obviously you want someone who is well versed in what you're working on, but many of my peers have found that it's more important that an advisor's personality and mentoring style line up with what you want, rather than making sure your committee is interested in exactly what you're interested in. Ask questions about a potential advisor's mentoring style (especially helpful to ask dissertators/people farther along if you can) — do they answer email promptly? Are they often on research leave and difficult to get a hold of? Do they let you know of relevant conferences and fellowships to apply for?
This is a lot of information and I know the decision process can be overwhelming. Feel free to PM if you have any specific questions about the process and good luck to you all!