For me, I have a great social life with my friends from uni... I sort of find the "imposed" social life at college a bit strange, and the routine would quite frankly not work for me... working two jobs plus uni I would never be at dinner at 5pm. I got really involved in the res events at housing but found that there weren't really people I really "clicked" with more than good acquaintences in housing and I had better friends from my course at uni. I can understand why college appeals to some people, and yeah I personally looked in to it when I was looking at unis and considered it, but at the end of the day, it is just a place to sleep, and the social life etc is what you make of it. My friend at college says that there are "study ghosts" at her college who don't get out and about amongst it etc. It depends on you a lot as well as the college.
I guess what I mean by the just a place to sleep thing is that the main purpose of college is to house you while you go to uni... I wouldn't agonize so much about it, I would pick more based on your course, if you are the type of person that suits college life I'm sure you will have a good time no matter what college you end up at, and you won't end up regretting your choice. The uni degree is more important than what college you went to.