Most of the students I've met so far seem happy. We help each other out as much as possible. <-- I really think this is key, and makes for a great environment. Within our class, we're always sending out useful links and documents. Even though we don't have a lot of cross-class interaction, I've felt whenever I do get a chance to hang out with upperclassmen, they are always up for answering questions, sometimes they send us useful emails with study tools, the 2nd years set up an informal mentoring program so you would have someone to talk to if you needed that structure (but I've found 3rd and 4th years who also readily offer their contact information and make themselves available as a support system), and they do a presentation at the beginning of each new theme to give us a heads up about what to expect, which books they actually found useful, etc.
What I don't like so far:
It's hard to find information! As I'm sure you've gathered 😉 There's no convenient guidebook, the info on the web is scattered and it isn't always complete and there's so much to keep track of anyway. The best way to find out anything seems to involve proactivity on your part and asking lots of different people questions until you find people who are knowledgeable enough. But as mentioned above, at least everyone's happy to answer questions!
If you have the luxury of choice, then you probably want to start considering what your priorities are and find out if the school matches that list. If you have more specific questions, let me know.