Heading to Sei this weekend ...
I went last summer, and liked it a lot aside from the high prices of the very small dishes. The wasabi guacamole comes with unlimited chips, so in case you can't fill up on the other small plates, this one's a good one to have on the table. The fish & chips roll is pretty unique. It's got a lot of different textures, but it's very fried. The yuzu cured chicken is pretty bland.
From looking at the menu, there's nothing else that I tried there. If they have the scallops with lentil puree, then order it for sure - it was absolutely delicious. Have a great time!