I'm currently a UA 2P. Before I start planning MRs for 2007 in order to reach at least 1P, I'm wondering if I should jump ship and go with another FF program.

They all have their pros and cons and with SFO being a UA hub, I'm probably better off staying put. However, if anyone else from the Bay Area can recommend a better program, let me know....

It all depends what your flying patterns are. AA is weak in the direction of Asia/Australia, but if you're redeeming miles in that direction you can choose from Qantas, Cathay, and JAL. I tend to build my miles on domestic and Europe, and spend them in the direction of Asia/Australia. AA is certainly competitive farewise (I have three $337 base fare Europe tickets over the next 4 months).

AA does offer reduced mileage awards through their credit card. SFO-Newark is 17,500 miles this quarter, for instance.

The free domestic upgrade program for top tier flyers, and elimination of "More Room throughout Coach", may have you leaning towards staying with UA, where you might have a better shot at upgrades and more legroom. If you're aiming for 1K, though, AA's equivalent tier offers quite a few benefits, including space available domestic upgrades (I've cleared 49 of 50 requests this year).

UA offers the most choice of flights from SFO, so unless you fly specific routes that other airlines offer better choices than UA does, UA is probably your best bet (as long as you stay elite enough to use the short checkin lines). If you stay with UA as your primary, AS makes a good backup to collect miles from odd AA, AS, CO, DL, and NW flights that you may occasionally fly.

AS may be worth checking out as your primary program if you do mostly west coast flying, particularly involving AS' hubs at PDX and SEA. As noted above, AS has many partners to collect mileage from as well.

If you fly a lot of short hops, would rather fly from OAK (that is closer to your stated location), and care only about free flights instead of elite perks, WN is worth a look.