In my case, NW Worldperks is the best for me and I live in SFO. As many have mentioned, its Elite program is one of the most generous as far as domestic upgrades is concerned and the percentage of successful upgrades, even for Silvers, seem a bit better than other programs. In addition, this program allows you to redeem awards by splitting it in either Y and J.

Having said that, if you plan to redeem awards to fly internationally, UA has the best group of foreign carriers under *A. I used to belong to US and the awards availability of *A partners was great in my experience. Remeber that UA, LH, SQ, NH and NZ still offer a F/C product and J/C on OS and BD are excellent too while on Skyteam only AF and KE have F (although as many have reported, KE F or J is not up to par with the likes of SQ or CX). Whichever program you choose, it has to be best tailored to your personal preferences.