The true strength of this sound font lies in retro gaming. Whether it be old windows games that use MIDI for music, or games running through DosBox that use devices that also conform to the same standard (Sound Blaster awe32, Roland SC series, etc...). Most other sound fonts will have inconsistencies and annoyances across the entire library of retro games for PC. But not GS Fluidsynth v1.44. Every game sounds great.
None. It's unfair to criticize it for not being the best when it is less than 35MB in size. That's like comparing an orchestra to a ukulele.