Just wanted to give some feedback after trying mbf204 on my two DOS PCs.
PC#1-486DX2-66, Cirrus Logic 5428 VLB, SB16 CT2800
-slightly slower performance to stock Doom (21 FPS vs. 25 FPS)
-640x400 runs between 5-8 FPS, but surprisingly it feels mostly playable
-audio detection and playback is flawless
PC#2-POD200MMX, TNT2 M64, Audician 32 Plus with DreamBlaster S1 DB
-VGA performance is over 100 FPS, 640x400 is still very fast at 85 FPS
-audio detection/performance issues galore*
*auto detection detects WSS, which does not work. Manually setting SB Pro works great for digital effects. I had an issue with MIDI--auto-detection picked OPL3, which worked. I manually selected MPU401, which worked. Then I manually selected OPL again, and this time it did not work. I manually went back to MPU401 and it did not work. I could never get MIDI music to play again after that initial auto-detection.
edit: I just remembered, manually setting SB Pro on the 2nd system is not flawless. It only plays audio in the left channel. I tried setting to the other SB/Adlib options, but they all either don't work, or work only on the left channel. Probably a compatibility issue with the Audician?