Curious -- what is your favorite frequent flier program, and why? I am a member of two at the moment (US Airways and AirTran), though I don't have enough miles yet on either to be able to judge how good they are. Are some programs better than others, or are they all pretty similar?
I was also wondering whether it's worth being loyal to one airline in order to build up FF miles. I've heard a lot about it being harder to redeem miles these days than it used to be -- is that true? What experiences have you guys had?
Thanks for any feedback!