jigglypuff

tl;dr this is a HARD problem. Before I started grad school, I would've told you Great School, no question. Now that I'm done and did a postdoc in a small college town that was OK at best and work in industry in a city I love...I don't know, man. Location and quality of life, IMO, is so important. I'm a big fan of treating a PhD program as a phase of your life - not some temporary, supra-existential chunk of Limbo time, but as an actual period of your life in which you deserve to be happy and develop yourself as a person and not just a professional. Balancing the two of them is really important.
I'm tempted to say that if you really believe "it's hard to go wrong with either," then why not go with the place where you really want to live and where you are pretty sure you can be happy?
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The long version:
1. Fit is king. If Great School has research interests that are closer to yours, then it seems like it's probably a better fit for you.
2. I went to an Ivy in a very, very expensive city (Columbia, in New York). You get by, and can even thrive. I lived with roommates and/or in small apartments the entire time I was there, but there are unparalleled opportunities for work and play in large cities. It just kind of depends on what you value, what makes you tick. If you like lots of space and wide-open vistas, a tiny apartment in Boston or Philly or New York may drive you nuts. If you want to eat greasy pizza at a hole in the wall at 3:12 am or get Sri Lankan food delivered to your door or take in world-renowned ballet or opera in your downtime, then a big city is kind of the only place you can do that.
3. I will always appreciate and never regret the seven years I spent in New York. Life-defining opportunity, even while broke. Location in grad school is far more important than I gave it credit for before I was applying.
4. Doing research that you would kill to do is one of the only ways to maintain your sanity in graduate school. When you wake up in a cold sweat early one morning during your third year wondering why you are doing this to yourself, remembering that you are asking and answering the questions you are passionate about is what soothes you back to sleep (or, more likely, eases you out of bed to get a coffee and start reading). I'm half-joking, but seriously, there's something really special and joyful about digging into something you LOVE for five years straight. You want to be at a place where you can really do that. It sounds like Great School is. Is Ivy?
5. I went to an Ivy that also had a reputation for neglecting its students, which in my opinion was mostly true (it depended a lot on the department). In my opinion, this also wasn't so bad...but that depended a lot on the student and the professor. I had mentors who were pretty good to really great, and they would make time for me if I was proactive about seeking it out (but wouldn't necessarily come find me on their own, which I don't see as a problem). I had excellent research mentorship from people at the top of their field. And I would say in my case, it pushed me to be more independent: to come to meetings with mentors prepared with agendas and notes; to seek out multiple mentors from different institutions to give me what I needed when my main ones were missing in action; to think deeply about what I wanted and what my research interests were (and not my mentors'); to gently push back against things I did not want to do. Is this a pro over having a more nurturing mentor? I don't know. I have some friends who had super nurturing labs and mentors and that experience sounds lovely. It also sounds smothering, to someone who never had that. I kind of liked the fact that my mentors didn't really care where I was or what I was doing at specific hours of the day as long as I was turning in good work consistently. I'd also say that the 'friction' required to get stuff done has helped me in my professional career afterwards - I'm much better at pushing things forward and taking a proactive approach (and bringing attention to myself and the stuff I'm doing) than I would've been otherwise, and it's been noticed.
The advice I always give students looking at my program is that if you're already a person who's got well-defined ideas about what you want to do and a sense of self-assured independence, attending a department with somewhat-neglectful (I say that sort-of-affectionately) faculty isn't necessarily something that will destroy you.
6. Citations, or publications? Do the professors at Great School publish more prolifically than the faculty at Ivy? take note of that. You need publications, and one of the best ways to get them early on is to jump onto a publication a professor or PI is doing.
7. Is the Ivy actually a more prestigious program in your field, or are you just attending to overall prestige?
 

I realised that I probably could have completed a semester's worth of intensive language-learning with the time I spent refreshing my e-mail, checking app portals and visiting this site. So I did two things: I started learning Hebrew on Duolingo, and I cracked open Musil's 1130-page Man Without Qualities.
Both have proved engaging, even addictive, and have lessened my impatience.

I realised that I probably could have completed a semester's worth of intensive language-learning with the time I spent refreshing my e-mail, checking app portals and visiting this site. So I did two things: I started learning Hebrew on Duolingo, and I cracked open Musil's 1130-page Man Without Qualities.
Both have proved engaging, even addictive, and have lessened my impatience.

Hey Kat! I've applied to Oxford's MSt (March deadline round), Cambridge's MPhil in European Literatures, Birmingham (buzzing German Studies scene), and will be applying to the MA Deutschsprachige Literaturen at Hamburg.  Universität Bern also has a highly unusual and eclectic German course offering - and the Robert-Walser-Zentrum nearby - so I wouldn't be sad to go there. Are you also considering the UK?
 
(Edit: just saw that you're going to Penn State!)

@jigglypuff I'm currently doing the MPhil in European Literature at Cambridge. It's a great program, good luck with all your applications!

I've applied to the PhD at NYU and M.A. at Columbia. If both fall through, I'll probably stick to Masters programmes in Germany/Switzerland/Britain.