Its definately possible to live up at the medical school, I've done it for the past two years and I haven't had a problem. The biggest drawback is you gotta get up a lot earlier than if you lived literally across the street in Stiles. The advantages are cheaper apartments, nicer area (my opinion, not crazy about big cities), get to get away from school when you are done the other problem is I think you would almost have to have a car to go get groceries and things like that, things are more spread out in East Falls.
The shuttle is fine, so I don't know where you heard its unreliable. I have taken the shuttle for the past two years just about everyday and never had a problem, I think its broken down twice since I have been here. Sometimes it fills up but they usually let you stand or its not a big deal to wait 15 mins for the next one in the AM. Living by the med school is easier during MSP cause class doesnt start till 9AM; in IMS sometimes class starts at 8AM (but they record everything so you dont actually have to be there). If you have any other questions just let me know.