I've heard that the place at Cosmopolitan has an excellent sushi offering, but I will leave it to Jaidee1 to elaborate . . .
Foodies will tell you the best Sushi in Las Vegas is off-strip. .
few years ago, friend who works in vegas said that, I cant remember the name of the damn place he suggested though
Ive only had sushi on the strip from Nobu at CP, it never disappoints, its fresh, made right in front of you but also expensive.