You make a very good point here. Cambridge is a pretty intense place intellectually and I thrive on it to some degree. I do know some faculty and grad students in the dept. at Harvard and they are very friendly, but I am sure there are petty competitions and fights like any other department. At UCLA I certainly think I would have more contact with the profs and it is smaller dept with fewer students (which may be a bad thing), whereas there are 50 grad student at Harvard and nearly 20 faculty, but it is a very active place.