Twice! We went twice during our short vacation in Vegas!
In all, we had the French toast, huevos rancheros, some kind of omelette with avocados and salsa (the name escapes me). The French toast is amazing. Get it covered in granola. It is sweet, fluffy, and textured all at the same time. We couldn't get enough of it, and normally I'm done with French toast after a pitiful half-slice. The huevos rancheros were very savory and had many different flavors and textures.
If you can ignore the dated Wynn decor and the incredibly cheesy and unflattering bright pink hostess outfit, this is where you want to spend your time. Bonus: no two-hour wait for the buffet, which is about 50 feet away.