Well, my experience at White Castle Las Vegas was consistent with a lot of others: just short of bad.
We stopped by midday and ordered one of the slider meals, adding mozzarella sticks to it. In the long wait for our food, I noticed that every person working behind the counter looked miserable. Everyone.
The food that comes out of this kitchen (despite its fast food quality) does not equate to the product sold elsewhere. Add to this the fact that prices are marked up to "Strip value."
Come to the Casino Royale to grab a few cheap beers at the bar adjacent to this place, but don't feel bad if you decide to skip White Castle.