I need to stay two nights (Sat & Sun) near SFO next month - preferably somewhere which has a free shuttle from the airport. There seem to be 4 choices: Westin (stayed there before - it's OK, but nothing special), two Sheratons and a Four Points. The best price I can see is US$115 per night.

Any thoughts on which is best or how to get good rates (I am SPG Platinum)?

Thanks in advance.