I have found CM to charge a premium because of their reliability and on-time departures, but to be honest, their product is severely lacking, and PTY's facilities as a hub are embarrassing.
I too will be renewing only to Gold, but I have a feeling it won't last another year, because I am not happy with the product.
Their service is average, and they do have a unique value proposition: I don't think I've had another international airline be able to do same-day changes internationally and give complimentary upgrades at the pace that Copa does. The downside is that their premium cabin is so much worse than Avianca, LAN, and even Aeromexico. All these airlines give complimentary upgrades as well.
It feels like I'm flying CO from the 2000's, down to the dated interiors and CO-modeled Copa Club.
For what it's worth, I am also turning away from AA because of all the EP devaluations.