I have not heard the AA, other than briefly at a show, but have been living with the GNSC Reference Mod Opus 21 for a few months now and would recommend you talk to Steve about modding it before moving on to another player. It's a special player once he's done with it. Eerily spacious staging and realistic imaging, dynamics and tonality are as good as I've found, and a very non-fatiguing approach to resolving detail that I really enjoy.
Audio Aero Capitole or GNS mod on Opus 21
OK I have decided upgrading to the Capitole, but am now wondering if I should just send my Opus 21 to Steve for the reference upgrade. Any opinions on these two players.