Japonais is a personal favorite and I have done a bee-line here the last three times I have been in Las Vegas. The concept is Japanese/French fusion. People can say what they will about fusion. But if you're going to fuse two cultures together at dinner, it's hard to go wrong with those of France and Japan. I have had the opportunity to try significant portions of the menu, and gravitate towards the sushi.
My favorites among a few categories...
Maki Mono: Panko Shrimp
Hot Appetizer: Sweet and Sour Calamari
Main Course: Tuna Steak
Specifics aside, everything on the menu is, at minimum, very good. The worst thing I can say about Japonais is that its best offerings are overrated. Case in point, its more notorious specialties - like the tuna tuna salmon and the lobster spring rolls - have actually been among my least favorite. Especially the former. But again, the menu is very good overall.