<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by MileKing:
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.</font>
I think this is potentially a very serious problem. 16 credits per year is indeed quite a lot to ask for an infrequent traveler. Thus, an infrequent traveler may be able to get a reward with a regular airline after three (or more) years of flying, but possibly never with a LCC. At least regular airline miles almost never expire.
I think "incremental" rewards (such as one-way flights of companion flights) would alleviate this problem quite a bit. (IIRC, AirTran program allows (or used to allow, before the recent changes) one-way awards and one-way upgrades.)