I personally use SampleLord:
https://www.samplelord.com/ I've tried sforzando, but wasn't impressed. SampleLord has LOADS more options.
The only downside it's 32 bit, but it's so efficient it hasn't been an issue for me. I bought it originally to use with my V-Machine (a seriously under-powered hardware VST player) for live use, which I believe it has special support for.
Another one I use occasionally is DSK SF2 :
http://www.dskmusic.com/dsk-sf2-v2/ which is free.
Again it's 32 bit, but this one has portamento which is cool for some sounds. The issue with this one is it plays some soundfonts in mono. There's some extra panning information in the soundfont spec it relies on, and my soundfonts didn't have it. I did write a java program to fix the sf2 files, which if I can remember correctly might have fixed it, but it was 3-4 years ago.
Anyhow, another 2 for you to try out.
M.