When I go to Vegas, I usually go from Friday afternoon until Sunday afternoon/evening. The thing with my friends and I is that we don't eat the first two days there. Well, sorta. I mean we do kinda eat I guess, but our typical meals the first two days are really cheap (think McDonalds or Chipotle) or just alcohol - usually the latter. We would much rather save a trip to the buffet until our last day there seeing that we won't have to be wearing bikinis for the day pool parties or tight dresses at night for the clubs. No shame when we get to the buffet and stuff our faces.
Anyways, one of my favorite buffets in Vegas is the one located at the Belagio. It's about $25 for the lunch price and I think about $30 for the dinner. For an extra $5, you can opt for the endless mimosas option too! My friends and I typically go around 3-4 in the afternoon because it'll still have breakfast and lunch items, but also that's sort of around the time they start putting out dinner items. Call me weird, but I'll still enjoy bacon and waffles at 4 in the afternoon.
The food here is absolutely amazing. They have a huge selection to choose from, so you'll definitely find something that will fit your mood. Can't stress how much you should always make room for desserts because they have some of THE best choices to try out.
Overall, I would definitely go back again. I've been there countless times and despite the long wait at times, I've enjoyed every trip.