As an AA Plat I am batting 100% upgrades this year on the routes I fly. I cannot say the same thing as a CO Plat. Of course on some routes ERJs are the only thing offered on CO so upgrades are out of the question. This year when weather and mechanicals have caused delays AA has brought me home on the same day, CO has taken an extra day. So, I will gladly ditch them. I will continue to fly AA domestic and pacific flights, after all as an AA PLAT I get lounge access, I need to be a PLAT on CO to do it, and switch to LH for European flights. As an FLT (*A silver) I get lounge access, on time flights, an occasional op-up, and complementary drinks on TATL trips. Plus I am really close to the 2 million mile mark on AA to have PLAT for life.
It has been fun.