There are pretty limited options for Sushi on Madison's east side. For the best in the area you will need to head downtown, the west side also has at least one solid offering. But when Takumi opened it was a definite step up from what used to be availble on the far east side. I favor nigiri and the fish here has never dissapointed.
The only two complaints I would mention are that the chef's choice dinner meal always includes the exact same fish varieties and I much prefer the spicy tuna rolls that consist of chunks of tuna vs the ground up spicy mayo blend that Takumi serves. That being said Takumi is very conveniently located, reasonably priced, and the food quality has always been very good.