Personally, I think it's hard to do too much of a strict comparison right now because service levels in domestic F are in a free fall for most airlines right now.
I had considered AA's product to be the best domestic F product for quite a while, but they've been reducing the service as part of their cost cutting measures. Admittedly, though, I do like the Recaro seats in AA's F.
Overall, though, I would argue that CO's domestic F product is the equal of anyone else's at this point.
Steve