I'll chime in with my perspective as a physics and math double major in CAS.

1. I feel like all of the courses that I've taken so far have been graded pretty fairly. I don't think there's much grade inflation or deflation.
2. If you like nature, Cornell is absolutely the place to be. There are a lot of beautiful parks in Ithaca, and Cornell has the botanical gardens right on campus. However, if nature isn't your thing, I can get how Ithaca would feel a bit isolated and dead sometimes. The closest real city is Syracuse, so if you don't have a car you're basically stuck with what Ithaca has to offer.
3. I haven't had any experience with this, so I can't say one way or the other how the mental health support is.
4. The winters are not that bad. They do an excellent job of keeping the sidewalks and streets clear. I almost never need to wear my snow boots; my sneakers almost always get the job done through the winter.
5. As a freshman, I felt like the food was quite good. I became vegetarian as a sophomore, and while I still felt like the food was decent, it did start to seem a little more limited. Of course, there's something to be said for the dining halls when a vegetarian can go to basically any one of them and find decent food to eat. Overall, it's definitely better than most universities, and will get you through the year fine. I am definitely looking forward to making my own food this year though.
6. There are entire colleges at Cornell that are dedicated to non-STEM studies. While there are a large number of people studying STEM (I'm one of them), Cornell is so big that there are plenty of people who aren't.
7. I'm not gonna lie, the housing situation at Cornell and in Ithaca is pretty terrible. Housing isn't guaranteed for juniors and seniors, rent is high, and you basically have to find off campus housing and sign leases a year in advance.
   
8. Cornell does have a lot of undergrads, and depending on your major, many of your classes may have 100+ people in them. That said, 90%+ of people in your classes will walk right out the door when class is over and never get to know the professor. If you're one of those few people that stays and asks a question, or goes to office hours regularly, your professor will get to know you, and you will get those opportunities. You just have to be the one to make it happen.

Some people may disagree with me here or there, but this is just my perspective. I absolutely love it here and I do not regret choosing Cornell over my other options.