I've never ridden an EC or MC spec GAS GAS so I can't speak to that, however..... I'd put my 01 XC250 up against any bike in the 250 class (Jap, Euro whatever). My riding buds ride KX's, YZ's CR's WRF's etc and they never pass up a chance to take a spin on my GG. I haven't heard any complaints about the power. Two of these buddies are selling their Yamahas and are going to buy Gas Gas when the 02 models arrive.
When I was in the restraunt business, people would often ask "what wine would be best with this meal?" I always told them... "the wine you like best"
Bike selection is all about personal preference... ride what you like.
e.