A couple of questions about CO for those who've already posted here:

- At the lowest elite level, is there usually a hold time on the phone when making reservations or changing flights? At the mid-tier level, nearly all airlines will serve you promptly, but different airlines take very different approaches with their phone service to 25K flyers (for example, TW doesn't provide a separate number until their 50K level; UA has a separate number but it still requires a long hold time; AA and US seem to serve you promptly unless they are having major cancellations).

- How available are the complimentary domestic upgrades to the lowest level elites? Seems like the only possible downside to CO's system is that F would always be full of the higher elites, leaving the 25K-level flyers without many upgrades. Once you hit the mid-tier level, it sounds like CO's system is far superior to most others. (In my experience as an AA Plat: I get the upgrade 75% of the time, but there's a limit of free ones before I have to buy more e-upgrades.)

- Wilro: Does CO give you lounge access at some level? Or were you talking about another airline? I know AA and US give occasional day-passes to their elites, but that's it. TW used to run promos where you can earn Ambassador's Club access with a few RT purchases, but I imagine that those promos are gone forever.