CT2940: Looks like a SB16 Vibra to me, so it most likely has the "hanging notes" bug. I cannot see an OPL3 chip as well. SB16 cards are also not fully SBPro compatible.

Acer Magic S20: Opti MAD16 card with CS4231 codec, will do SBPro and WSS. There is a genuine OPL3 as well and the MPU401 interface should work correctly. The MAD16 chips may have problems with some older DOS games resulting in distorted PCM playback but these situations are rare.

All in all, I would use the Acer card for DOS games.

A Pentium 100 can take advantage of the "12 bit" capability of the SB16. No polyphony issues, digi effects will be more fluid.
If your CT2940 has the OPL-L chip then it is a perfect OPL3 alternative.

The Acer S20 is a very capable SB Pro 2 clone, with some polyphony issues but it is just as noisless as the Vibra. Bug-free MPU401 confirmed.

Actually I keep BOTH these cards in one of my machines 😎

For older games, you will be using the Acer S20 more.
But the majority of general midi games can also take advantage of a better digi card, so in such scenarios you can use a DB on the S20 and play digi/effects on the SB16.

Is there a driver package or initilialization app for the S20? This is a new card for me, never had a soundcard with either opti or crystal chipsets so I'm not sure how they are supposed to work aside from a set=blaster line somewhere.

Drivers can be found e.g. here: http://download.solodrivers.com/gestor_downlo … do/opti/82c929/
929d_w.exe contains DOS and Win3.x drivers.