I am currently a double major in physics and EECS about to graduate, so my experience has to be broken down by majors.
Part I: the academics
A) Physics: I found the physics department at MIT amazing. We have 70-80 physics majors each year, which means you'll always find other people to pset with easily, and makes the department devote a significant effort to make the undergrad education stellar. In fact, they always try to have the best lecturers (Allan Adams, Alan Guth etc...) in the undergrad class. The major is really well thought out, especially their quantum sequence. If you are planning to go to grad school, makes sure to take their WHOLE quantum sequence (8.04, 8.05, 8.06). They are life-changing classes. The problem sets have consistently been enlightening, mind-opening and challenging but not impossible (ok, some of the grad psets i got might have been on the verge of impossible). You will notice the smartest physics/math majors are also the most humble: this is one of the traits i liked best about MIT. In this pressure-cooker and purist environment, arrogance has no place.
EECS: Because the department is so large, the classes definitely will feel impersonal, until you hit your grad-level classes. In general, i thought the intro classes well thought out, however i found significant complaints. This is because people come in with such a wide background (not knowing how to script "hello world" to having implemented as OS), that the experience depends highly on your starting level. The gist of the education in EECS, however is the labs. I learnt much less from doing problem sets, or studying for finals (you still have to do that). THe problem sets are less interesting and challenging, however the labs/projects will chew your soul, swallow it, digest it and regurgitate it. Some of the grad-level projects are extremely time-consuming, but the feeling of satisfaction at the end will be proportional to the amount of frustration you felt while doing them. If you are a hands-on person, the EECS department would definitely be a good fit. I have mixed feelings about my education in this department, but overall, I will have to admit that studying EECS drastically the way I think about designing complex, real-world systems for the better. Sometimes, i felt it was busy-work and overwhelming, but in the end, going through the the crap-work was necessary for my personal development. Furthermore, the job opportunities for EECS at MIT are limitless. I get spammed by internship offers from all kinds of places, and I don't even make particular efforts to get recruited.
Other students: I find it nice at MIT that students are a lot less likely to judge you. You will find your typical jock, your cheerleader, but what is nice is they all mingle
because in the end, you are judged by your academics. And you can be the most popular guy in high school, it doesn't matter when you come here if you are stuck on a differential equation. The students are extremely varied, probably moreso at MIT than at any other college campuses.
There's definitely a minority (~3%) that might have some type of social problem, and lock themselves up doing work. But the vast majority are humble, smart and engaging. There's also a large culture of collaboration, of "we are in this shit together", of us vs. MIT.
Research: The research opportunities are are definitely what you make of it. I know people who put in more time into their research than their classes, and others who slack off and get nothing done. But all of them had an easy time finding a group to work with. Make sure you have the maturity to monitor yourself before you ask for a research position. The problem is not that the professor will refuse, it is that he will give you so much freedom you might end up accomplishing nothing at all. I personally prefer doing UROP's during the summer, since I'm so busy during the semester research is just not an option.
Sports: What is nice about sports is that while being at the lower end level (div III type), it makes it much easier for the typical undergrad to participate. Something like 20% of MIT students do varsity sports. There are a lot of pick-up games of soccer, frisbee etc.. on Briggs field, especially during the spring/summer, so you will not get bored.Food: dining is good but really expensive because it is Cambridge. I personally cook for myself, and there are plenty of places on campus for quick snacks. This are could be improved though.