The other opinions are probably by people who are transplants from another part of the country. In all honesty, Cambridge is in no way a great city. It is terribly dirty, full of people who think they're better than everyone else, and is a haven for people who would rather prefer the "small town feel". Ask any student in Cambridge and they'll say they haven't really ventured into Boston because it's "too big for them". Open your minds, hop on the Red/Orange line, and go somewhere you haven't been. In short, Cambridge just sucks, it's poor, run-down, terrible, and is nothing like Boston. There is no history. The beautiful brownstones that litter Boston are rare in Cambridge. The city is full of people who think they're god's gift to Earth. I lived in Boston earlier, moved to Cambridge, and now regret it, and definitely am moving back. If you like people that are normal, move to Boston's South End or Fenway. Back Bay tends to be full of young professionals and upper-class elites, but everywhere else is amazing and clean to live in. Cambridge on the other hand, is full of "biker emo's" who don't follow rules of the road (I bike myself, and often find myself yelling profanities at them), elitist people who think rules don't apply to them, closed minded townies from suburbs, and people who just suck in general. Do this: go to John Harvard's Brew House and Boston Beer Works, and see what you like better. If you like the former better, then sorry, I just hope I don't see you on the streets. Cambridge has a lot of good business establishments, too bad the people don't reflect that (other than tourists, I just love tourists).
Edit: I don't mind people who have "townie" views...it's just not for me. This is just my opinion.