One of the things that always strikes me about Japanese restaurants is how "americanized" they tend to be. This is not so at Ichiza, which is probably my favourite place to eat in Las Vegas. It's an izakaya so forget the menu and order off the wall. That's where all the good stuff is anyway including the "Eel Kaarage tempura roll" (or as I like to call it: the best thing that I have eaten in my entire life). You won't find any "all you can eat" sushi here but if you're looking for good, authentic Japanese fare, this is definitely the place to go.
Only con: Be prepared to wait for a long time to get in, especially if you're going during meal times. It's worth it though.