Fogo is definitely better than Pampas. I haven't been to the one at Mirage - but I've heard mixed reviews. I've never heard a bad review of Fogo. I suggest you go there.
Fogo de Chao definitely gets my vote. Although I have not dined at their Las Vegas location (on Flamingo, just east of the Strip), I have eaten at the one in downtown Minneapolis several times. Great salad bar and the meat selection is delicious. The waitstaff has always been terrific. Expansive wine list.
Glasses can affect your vison; especially when they have been emptied several times.....
We ate at Fogo last month and it was o.k. They kept bringing Sirlion to the table. Top Sirlion House Sirlion Bottom Sirlion. I asked the waiters to bring a diffrent cut of meat Filet or Ribye and they said it wasnt ready yet. 4 of us for dinner at $248.00 for sirlion. Never again. I can get sirlion at golden corral or any other cheap steak house for under that price......