I have owned both and Portugal and Tpk have it correct. The Cary is more forward (not a bad thing if that's what you want/need) but for dynamics and more "analog-like" sound, it's the Opus. The other nice thing about the Opus, is if you decide someday to invest the money for the GNSC Reference mods, it takes a great player to a whole other level.
See the 5 player shootout thread here on A'Gon, the GNSC Opus was compared with 4 players that are considered elite, and run 3-4x the cost of a modded Opus, pretty good compliment to be considered with that crowd.