As far as authentic goes, this is a great place for sushi. Yasu-san takes great pains to make the sushi both artistic and well balanced for the palate. There are mostly simple, classic sushi offerings as well as some spectacular add ons like soba and tempura. Their tempura is some of the best I have tasted.
The only reason I didn't give it 5 stars is because for those that want more trendy sushi (ala "RA") or more americanized offerings this will be disappointing. I would recommend going somewhere else if more traditional fare is not preferred, leave the tables for us that love the classics.