-- This is only my personal thoughts through listening to the tracks, so make your own judgement --
-- -Armaetus --

GREAT:
Weeds GM3
SC-55 Patch93
Fatboy
Merlin Gold
Shadow 1.0

GOOD:
Arachno Soundfont v1
2GMGSMT
4GMGSMT
Chorium
Doom SNES
SGM v2.01
Titanic 200

OKAY:
eawpats
GravisUltrasound
RealFont 2.1
Unison

MEH:
32MbGMStereo
Timbres of Heaven Final
FluidR3 GM2
The Ultimate Megadrive Soundfont