Wave ROM is a complicated issue, it is an indication of the quality, but nothing more. It all depends on the technical creativity of the programmer in how he/she uses this wave ROM. That being said. Frank Rosenthall has 15 gigs of wave ROM (he can correct me if that's wrong or even greater then that, at this writing), so if he says his softsynth arranger sounds better then our keyboards, I believe.
Starkeeper