I've eaten at many a buffet in Las Vegas but not necessarily a lot of the higher-end buffets such as Bellagio's. Mostly this is due to the high cost of eating there when I would rather spend that money on a single entree at a regular restaurant. Last night I had the pleasure of attending the pre-opening of Aria with all meals and casino play comp'd. We had the choice of either the cafe or the buffet. Since there was a huge line to the cafe, we chose to head upstairs and see what was offered.
The buffet is very attractive physically with different levels to the seating area as you move through the room. The serving area surrounds the room, starting with salad and seafood and moving through the typical, yet sophisticated buffet faire. It ends with the dessert area which is less substantial than many buffets but did have some good treats.
The food ranges from crab legs and shrimp to veal bollanaise (at least on this particular night), from hummus to asian noodles. Again, much of the same stuff I've found at the Palms buffet or Wynn's. Compared to Wynn's buffet, the Aria does not compare in choice for dinner or selection in desserts. The food was of high quality at Aria but not worth the $30 after taxes it will cost for a dinner here.
Perhaps after the grand opening the selections will change. There are some issues with people lining up for the seafood when they may not realize you don't have to wait to move around the rest of the room; a bottleneck that almost ends up having people lining up near the entryway.
I would probably come here again only if the meal was comp'd. If I were a guest at the Aria this would be a good choice for a buffet as there is nothing else within walking distance from the casino (perhaps Bellagio but I've never eaten there) that would be any better, but maybe the walk will build up an appetite that any food can resolve.