I am not going to stick up for CO too much and I do think collecting CO miles for the sake of it is stupid (do AA instead), but for me as a mid-tier elite they are great. I fly regularly to Australia and so I can use a year of mid-tier elite flying to earn enough miles for one QF award (avaialability is not great, but it's usable if you travel alone and are flexible). And since I would never pay to upgrade, OP only has to do better than the equivalent of the 4*500 mile stickers I get per 10K flight miles on AA (or UA) to do well on that grounds. Which they do. Plus the planes are clean and (EWR apart) the staff are great.

Plus I am used to QF so even CO's award availability seems good...

I understand where y'all are coming from, and I understand that reward availability can suck for many routes, but for my personal circumstances, given I fly on routes mostly served by CO, I'm not unhappy with Onepass at all. YMMV, obviously, but there are two sides to the same coin.