I've never had an issue with my CO card. I'd suggest getting the Venture card that pays back 2% towards travel expenses (1% towards non-travel, but a bad deal IMO). It does cost $59/year, waived the first year, and gives you a 40000 point bonus the first year, which is worth $400, so you do come out ahead.

I used to use an American Air miles card exclusively until they stopped counting credit card mileage towards million mile status, and now use the CO card for most items.