As Las Vegas buffets go, it's OK. My most recent visit to Aria included two comp buffets, so it was a good deal. But it would have cost almost $80 for two of us on a Friday night - that would not have been worth it.
Service was good - waitress greeted us with a smile and was usually pretty available - or her counterpart was. Never wanted for beverages.
For the size of their buffet area, the selection is somewhat small. It's really best to walk through the whole thing first to determine what you want for dinner.
Good sushi, decent desserts - but not too much stands out there. My brother loved this place - preferred it over Bellagio. I disagree.