the reliability of the concerto with POKEY installed is scattered, at best. Smaller games 32k and 16k, seem to load fine, but most of the Supergame carts experienced a range of problems:
Ninja Golf would have major graphical corruption on the title screen, and be unplayable, in-game.
Motor Psycho, Fatal Run, Mean 18 all were unplayable and would either not load, or crash after the title screen.
One-On-One would crash after the title screen.
Double Dragon would crash after the title screen.
Rampage was hit or miss. Most of the time it would crash/be corrupted on the title screen.
Beef Drop would show a skewed gameplay screen, and be unplayable.
Pac-MAn Collection pokey would have a skewed board and be unplayable.
Most other games would play ok most of the time, but startup/menu crashes and crashes after selecting the games was every other try.
All of those games work 100% without pokey installed.