Sushiro has good sushi but it's expensive. When my girlfriend and I go there usually the bill is $50-60 for the pair.
I've never been to the Samurai for sushi, but their meals are top notch.
Yohei is alright, but their sushi is really basic. Mostly just rolls: seaweed, rice, and a small piece of fish. It wasn't bad, but Sushiro is better.
Stay away from Otawa. They charge Sushiro prices for Yohei-type sushi.
The only other place in the city that I've had Sushi is at a little restaurant off of 2nd Ave. called "Noodle King and Ice Cream Queen". It doesn't have a sit down restaurant kind of feel too it (more like a cafeteria feel, tbh) but it's super casual and the Sushi is on par with Sushiro for a fraction of the price. Might be worth checking out
Hope this helped!