Seems that the later cards had AMD chips, while my original version GUS has a Gravis GF1 chip on it.
If you're new to the GUS have a read of this thread, its got links to drivers and downloads, including patches for certain games to give GUS compatibility.
Install Gravis Ultrasound Properly, All files, No Errors (With Pictures!)
This is another good site:
http://www.gravisultrasound.com/
If you have at least 1MB of RAM on your GUS you can try the Pro Patches Lite, which is supposed be higher quality samples. They do sound slightly different to the default ones though.
The GUS excels in games that support it natively. In anything else its pretty hit and miss. It's Adlib/soundblaster FM emulation is woeful. I'm not really a fan of its General MIDI or MT32 emulation and the TSR's you have to deal with to make that work are a bit clunky.
But games with native support sound excellent.
If you're building a gaming rig with the GUS you'll probably want to keep a Sound Blaster or compatible in there as well.