Pros
People come to MIT for the caliber of co-workers and the prestige. In these regards, it lives up to expectations. The name carries a lot of weight. The professional connections can be quite valuable. There are chances to meet very important people, in a variety of fields, if you are willing to seek them out. The support for entrepreneurship is nice. The available resources are fantastic, I never have to think about ordering equipment, the money spigot is always on. The personal professional services seem helpful (Strategic Planning of Talent, etc.). The fact that both a pension and 401k are available is great, if you plan on staying for a long time. The competence of co-workers (in scientific/academic fields) is top notch, as is to be expected. The non-academic staff has seemed competent and understanding of the needs of researchers, in my limited experience.
Cons
It seems that the institute has a tendency to nickel-and-dime people for access to services. The campus gym charges staff an exorbitant fee (over $400/yr) for access. Very little is done to improve life outside of work for staff. The only reasonably priced health insurance requires using the on-campus clinic, which can be quite inconvenient. The tuition assistance is a complete joke, they offer so little money ($5,250 per calendar year) that you can at best afford to take one course at MIT per year without digging deep into your own pocket. At that rate, getting any kind of degree is not practical. Even auditing a course is prohibitively expensive. I am not sure about parking and daycare, but I hear they are bad. There is not much going on in the area, outside of MIT. There is very little socialization, or at least, you need to work hard to seek it out. There is very little nightlife. The area has all the problems of being urban, with few of the benefits. Cambridge is not a nice place, it is run down, dirty, ugly, and inconvenient. The rental prices are way above the equivalent purchase prices of the equivalent places. The quality of sub-$3000/month apartments is very poor (leaky, moldy, insufficient insulation, infested with bugs, etc). Any apartment under $3000/month is unlikely to be professionally managed, and most landlords are completely unresponsive. There is a very limited selection of restaurants, and most are not particularly good, and there are no real fast food options, and almost all places seem to have surprisingly limited hours. Parking a car around town is supposedly very difficult and parking enforcement is very aggressive.