I've never had a problem getting to SFO on time from the Oakland Hills provided I take the San Mateo Bridge. The only times I've had close calls was when I thought I'd like to see the city skyline one last time before leaving and chose to take the Bay Bridge. Even if there is an accident on 880, 92 or 101 I know enough of the backroads to get around it, getting stuck at the Bay Bridge toll plaza is a real bummer when you're running late for a flight. That said, I've never missed a flight, just a few close calls. I've never really considered taking BART but probably not a bad idea.