For those who don't know, the AWE64 is a wavetable card as well as a FM Synthesis card.
But having owned an AWE32 and SC-55 "back in the day", I was fairly disappointed at the AWE32's stock GM set and very impressed with the SC-55's. Add a little reverb on top of the SC-55 (tab out of your game and send a QuestStudios MIDI file, for example) and you really start to see the benefits of hardware modules. Serious ear candy, in a different but (mostly) no less impressive way to the MT-32.
The AWE banks sound like soundfonts. Some instruments work well, some less so. And of course most GM scores are balanced for the SC-55, so soundfonts will have instruments too loud, too quiet, respond to velocities different etc etc. So I'd be using the AWE for FM and the SC-55 for GM/GS.
I think now that I'm older, I appreciate the AWE banks more for what they are and not for what they aren't. But for balanced sounds in GM gaming, I wouldn't be using the AWE32 at least (not sure how improved the 64 is with memory and soundfonts).