HNflyer,

I think that the general consensus is that AA miles are worth a good amount more than CO miles. I don't have the AA miles, but if I did I certainly wouldn't trade them straight up for CO miles, and I live in Houston. CO is considered to have the worst availability of the majors, while AA is considered to have the best minus Southwest. If you can get the seats you want with the stopover at IAH, I'd hop all over it.