BART is about the only mass transit system that's worth the price of using it in the entire state, even though it increases the longer you travel and crime. The problem, and I speak with about a year's worth of experience, is that the bus lines to get to BART suck ass. The bus could take an hour for pick up and it was not cheap either. My fare at the time was ($2.10+$1.75 for BART*)*2 per day. Not only that, I also took a lot of opportunity cost by being on such a strict schedule. Could never go out and do miscellaneous chores, rarely benefited from transfers because I was at school for at least 3 to 8 hours, and couldn't even taken early morning or night classes because the bus line would either shut down or be so early that I physically couldn't wake up in time. I'm sure the fares have only gotten worse since then.
*I was close enough to the school to warrant a short BART trip, but the bus lines themselves didn't connect to the school.