My most recent visit to The Buffet at Wynn was on 7/14. I've literally been here a few dozen times; I'm pretty much a regular player in the poker room (best room by far!), so this is basically free cafeteria food -- 1st world problems :)
Well, the food quality for a buffet is great. Rarely is the food not fresh, but it does happen once in awhile. The decor is beautiful, and the food stations are kept clean and presentable. Most of the hostesses are quite friendly.
While the food is great, the selections are limited compared to my favorite buffets: the Bellagio and Rio.
The service is hit or miss. Most of the time it's decent to excellent, but on my latest visit, not one refill. Quite disappointing for a 5-star resort and a $40 buffet. If I had actually paid for the meal, I probably wouldn't come back for a long while. I do appreciate the good waiters/waitresses that have treated me very well over the years (Nicole is one of the best!), however I think it's time to take a break for now.
Overall 3.5 but rounded up since I'm a little biased -- the Wynn is my favorite casino to hang out at, and includes my favorite poker room.