in my experience, CO has EA at every gate. most CO'ers will whine and complain about it, but i think its great.

boarding whenever you want is huge for carry on travelers, b/c it almost gaurantees you an overhead bin and getting your luggage among the first is huge for checked baggage customers (i dont know if its just me, but my bag is the first one out at msy almost 90% of the time and always one of the earliest bags anywhere else).

the rest of the benefits that CO touts for EA arent that great b/c you dont usually get a chance to benefit from any (upgrades, etc), but i think its a very simple way for CO to stand out from the rest and thank its important customers at the same time.