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.