I have an AWE64 but never used it for DOS era stuff.
As mentioned, all AWE64s use Creative's imitation of the OPL3, not the real Yamaha version, so that's one possible criticism. However, most AWE32s are the same way, only a small subset of AWE32s have the Yamaha OPL3.
People used to prefer the AWE32 because it uses standard SIMMs, but there are adapters to use standard SIMMs on the AWE64. I don't know what the availability is like for those adapters.
Personally my most simple reason for preferring the AWE32 is because that's what I had back then, and I have a good model of it that works. That's my nostalgia, and I have none for the AWE64.
But since they're expensive nowadays, if I had to buy another card I'd have to give the AWE64 some thought.
Another option is the "Sound Blaster 32" (not AWE32). There's little practical difference between AWE and non-AWE.