On a whim, I had lunch at Sushi 21 (54 Mt. Auburn St, Watertown) today. I must say, quite good. The presentation was beautiful and while that may not contribute to the taste, it does contribute to my sense of authenticity.
My unagi w/ avocado maki was flavorful and delicious (actually better than the one i had at oishii too a couple weeks ago, although that meal was certainly better all told), my shrimp tempura roll (i may be californian, but I am still an american) was light and crunchy.. just right. And the white tuna seasonal special was fresh and just the right melt-in-your-mouth texture.
Coming from the SF area, I've frequently been disappointed by the sushi in this area but my meals at Oishii and Sushi 21 are starting to change my impression (while steadily draining my wallet...)