I've flown COPA to EZE and to RIO. The President's Club is nice in Panama. Their is plenty of duty free shoping if that is your bag. I found COPA F service very good, the FAs were very attentive. They really went to town for me as a Plat and ST2 person. I think I was a COstar at the time as well. The 737 are nice aircraft, you'll get a movie or show.

The tough problem is the arrival/departure times. I don't know why, but most SA airlines seem to fly overnight and in the early morning hours. A bit tough on the system.

But to answer your q, I would rather fly COPA than any other airline.