It's much smaller, but I'll say that DH (Independence Air) has a very straightforward one as well. One point per dollar spent on a ticket (there's a 2 points/$ promo right now), and 1500 points gets you a r/t in any available seat. It's basically the same as Southwest, but credits dollars instead of one-way trips.

Except for the aborted attempt to issue 0 EQM for cheap tickets, the US program has been pretty good to me. I only think once did I have to bug them about a promo not posting, and that was actually something I did wrong signing up for it. All of my flight miles and bonuses generally posted within two days, though I know others have had problems with them. I redeemed 11 award tickets for self and friends last year and didn't have problems with any of those (I did use the "rulebuster" option on a few because of the Sat night stay rule).