This is me and my wife's favorite sushi restaurant in the Madison area to date. My wife lived in Japan in 2 years and so she's a little picky about sushi -- me, I'll eat supermarket sushi without batting an eye but she'll only eat the good stuff.
Me, I know how to recognize the authenticity of a place by its clientele and Wasabi's is telling -- you'll see a lot of Japanese eating there, or at least in the half dozen visits I've made there I have.
Their rolls are always expertly prepared and seasoned, the only thing I've ever eaten here that I did not enjoy was sea urchin and I think that's solely because I discovered, after trying it for the first time, that I genuinely don't like sea urchin (as opposed to it being Wasabi's issue).
Their udon is also amazing -- my wife orders their yakisoba almost every time we come here because she says it is the closest she's had to the real deal in Japan.
For downtown lunches they have bento specials that include soup, rice, a little chicken hibachi, a little sushi (they have different varieties available), and a flavorful salad. It's a great value without leaving you overly full.