Doug B.
Yelp
While I am not someone who seeks out sushi, the people that I frequently find myself in the company of are, so I end up eating quite a bit of it.
Despite arriving with a large group, this place was able to seat and serve us efficiently, which can be a challenge at non-conveyor-belt-style sushi restaurants. I was impressed by that, at least. Note that we did have a reservation, but the place was not as crowded as I read it might be. We sat in the below-ground level -- probably because we were a big group and the implication was that we'd be there for a while ... and be noisy.
The service was very good. We ordered a variety of things (of course the maguro (tuna) that they're famous for... and the uni -- the edible part of the sea urchin -- which is, apparently a delicacy. (I think I can leave that one off my next order, but it was interesting to try once.) The tiny shrimp that we used as an appetizer were cooked well: crispy and just the right size for picking up with chopsticks while we had a beer. We mostly had sashimi, with a few wrapped items (like the uni and green sand -- more on that later).
The fish was simply plated and tasted fresh. We ordered some different "fattiness" levels of our tuna and it was fun to try the different types of the same fish. Each person received his own plate with each of 4 types (red, medium fatty, fatty, and broiled fatty), which made it convenient that we didn't have to pass plates around the large table.
In addition to the uni, we also had something sandy and green that translated loosely as "crab paste" that we ultimately determined was the liver (tomalley), I believe. Another delicacy and something to try once, but I think there is a reason I don't normally eat it on its own... to be fair, it wasn't really "sandy"... it just looked that way.
Miso-marinated black cod is one of my favorite preparation and we ordered a bit of that to try. Sure, it is a cooked dish at a sushi place, but it is still amazing when done right. The way they prepared it here resulted in a buttery fish with some caramelization and a light miso flavor. It was very nice, but not the star of the show. Several people in our group like eel, so we each had some "top quality sea eel" as well. It is not really my favorite, and I was pretty full by the time that one rotated in, but it was likewise simply plated.
The sake we had was very nice. I don't know much about sake, but it was a bit sweet but on the drier side, which paired well with the fatty tuna -- and helped clear things out after the uni and "crab paste". :|
There are many Sushizanmai locations besides this one and some may be significantly closer to where you are staying, so check Yelp first. This one was slightly better than another member of the chain in Roppongi, but I don't know that it was worth the extra travel time since my coworkers were staying there and it was a 10 minute walk from their hotel to the other one vs. a cab ride.