I'm not a big fan of Southwest, but for the LCC, it would seem they do have a very good program. It's very simple so as not to confuse travelers...no worrying about miles, fare classes, capacity controls, etc. Basically, one flight = 1 credit; get 16 credits and receive a free trip. Southwest's program delivers free trips and nothing but free trips. This may not be the most appealing thing to most FlyerTalkers, but for Southwest's market of price-conscious, relatively infrequent flyers, it is ideal.

The one drawback I can see is the one year expiration of credits. While not a problem for frequent flyers, infrequent flyers may have a difficult time accumulating 16 credits in one year. Thus, they never have a reachable goal and would tend to be less loyal. Granted, they don't take many flights anyway, but I would think an LCC would still want to encourage loyalty. Of course, these customers are perhaps focused only on price and thus wouldn't fly the LCC even if credits did not expire.