UCI undergrad for four years but figured Id share what I have discovered about housing:
On-campus: VDC norte is newer, but I have heard that they have rodent/pest problems and get atrocious cell phone reception from every major provider. They do have free AC though which impossible to find anywhere else in on campus housing. You WILL live for cheaper if you live in on-campus housing without a doubt, but on-campus stuff is pretty scarce and parking is very not-fun, although they are opening up a new parking structure this fall for housing.
Off-campus: More expensive and further. I highly recommend rancho san joaquin, it is 1.5 miles from the med campus and I bike it every day with no problem. No parking issues, bigger apartments, lower rent. There are other places too, like park ridge, but it is pretty far. If you want to stay close to campus you will be living in very cramped apartments with a parking situation that rivals UCLA. Thats why I think moving further away is better, plus you get exercise.