Definitely one of the better buffets in town (3.5 would be most accurate for the food; 3.0 for ambiance). Most dishes are well prepared and of good quality with flavors well balanced and the selection is a bit differentiated from standard buffet fare (e.g. garlic and herb naan and pepperoni pizza bagels). We were there for the brunch buffet and my husband says the cured and carved meat selections were quite tasty and the food stations are done in a visually appealing manner.
The room is spacious and open with plenty of filtered light and view of the pool area and trees; it's part of the Aria's "promenade venues" and continues the theme of plentiful filtered light, modern decor and open space. Thing is though, the buffet room gets a bit too loud (compared to other buffets, such as the Wynn) which takes away a bit from the upscale ambiance the place is supposed to have.
Hint for Vdara guests: don't take the tram and try to get there via the Crystals & Aria's main entrance. There's no need to trek through the smokey Aria casino, you can just walk out the Vdara lobby, across Harmon on the walk way over the street and into the Aria lobby. Head right on the second floor; from there and it's just a couple of yards.