For what it's worth, in the comparisons I've done between the EVH 50w and 100w Stealth, I found the 100w extends farther down the frequency spectrum and is able to develop more of a walloping low end because of that, and the voicings are just a little bit different between versions. The 100w tends to be a bit thicker in the mids while the 50w tends to be just a bit more "slinky" and slick sounding (in a good way) due to what sounds like a slight dip in the mids before gain.
HOWEVER, I was able to minimize the differences in the mids by using a GE-7 as a mid boost going into the 50w. Doing that brought back the thickness of the 100w and made the amps feel about the same overall, but the 100w still has an extended sub low end that I was never quite able to get from the 50w.
I don't think the 50w or 100w version is flat out better or worse though. They're different but they're both great amps.