I lived with two med students for roommates this year. We met thru our school's "roommate wanted" listing. One of them I didn't meet until two days before I moved in. The other one I met once just to make sure she seemed normal.
Personally, I like living with other med students. It's nice after a long day of studying to come home to someone who knows what you're going thru, and also someone to ask questions to if you don't understand something. Also, it was good for me in that having my roommates ask me questions made me realize I knew more than I thought (or less...depending on the subject! 😕 ). I wasn't close friends with my roomies, so we all led separate lives and different things going on so it didn't get to be 'too much'.
Personally, I would recommend meeting any potential roommates in person before living with them...some people may sound perfectly normal on the phone, but don't seem quite right when you meet them face-to-face...there are some med students in my class who give me the creeps!