I flew LAX-PTY-GRU in $1200 Y -> Ejecutiva. Aside from some baggage drama on the ground, the experience was fantastic. Great flight attendants, 2 meal services on each flight, on the flights between PTY and LAX they gave out amenity kits. The food is good. In GRU C class pax have access to the RG lounge, and of course in PTY you have the pclub.
Unfortunately, the link between CM and CO is a bit goofy in terms of reservations. Once you get upgraded you only get 100% EQM, KEEP YOUR RECEIPT showing full Y. It was a pain in the @$$ getting that fixed and it was the diff between 72k and 78k EQM.......