Roomies can be good, and bad. I lived with another dude for about 2 years, great times, we were good friends, we did stuff together, went out to places, got shitfaced a bunch, hunted chicks together, but in the end, he got pretty down over some girl and it ended pretty badly. Still friends, but not good buddies anymore.
Another time my wife and I (not married then) lived with her BFF for 3 years - totally destroyed that friendship, mostly due to the guy her friend was seeing - it was really fucked up.
I had to move out of another place with this roommate that turned out to be OCD clean freak. Oh and he was dating really underage chicks, like 15 yr olds when he was like 23. Bad idea to be in that house.
Another time I live with my good friend, 2 years of fun for all. His Gf was cheating on him and cuz of me and bro's before hoes, he totally caught em like pants down in-the-midst and there was no denying.
So it can be good and bad, in my experience, generally roomies are good. Just make sure you watch your stuff till you trust em.