Concur completely.

I'm facing a similar, but somewhat different decision.

I'm currently EXP on AA (with 70K already in the bag and 30K additional travel booked already to re-up for next year - they are the preferred carrier of my current employer), DL Platinum & lifetime Gold (with 2011 Platinum status already secured at about 90K w/rollover included - they are secondary carrier for my employer), and have CO Platinum (through a match) with about 5,000 miles this year. There is a moderate possibility that I may do heavy travel out of Denver next year... and I expect a couple more trips IAD-DEN for the rest of this year that are NOT on the company dime. I still have probably another 30K yet to book for this year. UA is not a company preferred carrier (in fact it is "out of policy" and requires justification if we book them), but it appears that CO is still "OK" if the price is right. I have nothing on UA this year.

I'm planning on crediting the DEN trips to CO even if it's on UA metal - I should make first tier on CO - the question is whether to try and stretch the other trips onto CO even if it falls short of Gold. Or do them on DL where I at least get the rollover benefit (which would allow me to secure PLT again next year with a couple of mileage runs).

I'll probably back off of DL in the future and move that travel to *A, but will probably not get to the magic 100K level, especially if I end up continuing on AA. AA has a much better program at the moment, who knows what the future will bring, as there's some chance I may change employers within a year (in which case the current environment between program devaluation and TSA makes me want to call a halt to flying).

Thoughts on that logic?