I've dined at Nobu five times and never gotten service above below average. One time the service was horrific and when we complained the server goose-egged his own tip on the credit card slip (party of 10, $1,700 tab and we were gonna just give him 15% but decided to roll with his suggestion).
As for the food it's 40-50% the quality of their NYC counterpart - and that's generous. Don't get me wrong I have all the respect in the world for Chef Matsuhisa, but I guess that's what happens when you open a restaurant 3,000 miles away with a dining area the size of a football field. Some dishes oversauced, others overcooked. No love, man, no love.
If you want Nobu style food for half the price take a trip off strip to Sen of Japan. If you're looking for high-end sushi on the strip Okada at the Wynn's the best I've had but I've yet to dine at Yellowtail (Bellagio) and friends tell me that's the best. I've also had a couple good meals at Shibuya (MGM).