Originally Posted by Boraxo

Agree 100%. For those of us who have personal automobiles, it is a no brainer (drive to OAK and park at Expresso parking).

SFO experience is a bit different as it is only 35 min from downtown SF to SFO on bart, and you go right into the international terminal (or 5 min walk from UA/AA terrminal)

Only reason to take bart to oak:

1) Tourist and you don't have/want/need a rental car.
2) Rush hour traffic makes it quicker to use bart (generally not true from other side of bay, but maybe from parts of silicon valley)
3) You are taking a 2 week trip and don't want to pay for parking that long.

As for the IOP, the bart ride itself will be 1 hour travel time, but don't forget to throw in waiting time (longer off peak) and the bus to oak which -depending on your luck, could take another 1/2 hour.