I really appreciate the responses. Before I posted my question, I had narrowed the candidates to AA, UA, and US. I didn't want to influence responses by saying that up front.

I faxed United this afternoon at 5:00 EDT requesting a comp to whichever premier level they think is appropriate, given my past activity with CO/NW.

There were really good reasons to choose AA or UA, and hearing from those of you with experience in each program was valuable. I don't think I can go wrong with either one. I think my opportunities for domestic upgrades will decrease, but if I am getting a 34-35 inch seat pitch in economy vs. CO's 31-inch when I get stuck in their "elite seating," I don't care.

I chose UA mainly because their elite qualification rules and partner mileage accrual opportunities seem to be more liberal. Although UA only has 10 flights a day from TPA vs AA's 19, their alliance w/US gives me about 20 more (not including crop dusters).

Of course, UA could say "no" in which case my next step would be an AA challenge. Either way, I am now sure that I am going to a better program.

Thanks again to everyone for your input, and I look forward to spending more time at FT.