Background: I have accounts with UA, AA, NW. In the past (up to about 2006) I have flown both UA and CO when they were cheapest, work put me on them, etc. Although I find them both fine in-flight, UA's ground staff within US48 consistently made me feel unwelcome, so at present, my UA account just collects miles for my occasional flight on SQ or NH. Although I primarily fly SkyTeam, it's more KL, NW and DL - the only route I fly on CO these days is NYC-EDI, which UA doesn't fly. I have ~40K miles in my UA account from years past, but have never attained elite status (nor even come close) on UA, and since I don't have a CO account, I obviously haven't attained it on CO either.

As I see it, I could keep the UA account as a going concern, and just have CO miles post to it once CO joins *A. Or, since I do fly CO more than I fly UA, I could burn my UA miles, pick up a CO account, and have future UA flights post to that.

I like CO better than UA based on past experience, but having not been a elite on either, and having not been into the RCCs, and all that, I realize that I'm woefully ignorant of factors that would be valuable in making the comparison. So... what do y'all think?

Oh, and one point, to save people the trouble of making comparisons on this factor: I don't drink, so who has which booze on the planes or in the clubs, and how much it does or doesn't cost, and whether it's self-serve or not, doesn't matter at all to me.