Big Sushi is my second favourite on the Bloor/Annex strip.
Things that make it unique from the others:
1) The BIG, comfy booths! Oh yeah. (At Sushi on Bloor I can get crammed into a small table and chair and have to sit near the doorway with 15 people waiting in the queue, talking loudly. This doesn't happen at Big Sushi. I get a huge booth with padded back rest far away from the entrance)
2) The waitresses actually wear kimono tops
3) Relaxing music (jazz usually) playing in the background
4) Plates shaped like a big fish (what can I say, I'm easily amused)
The menu has some unique maki options but for the most part it's a pretty standard menu. The lunch specials aren't *as* cheap as some others, there are a few specials for $5.99 but most are a few bucks more.
I also find the rolls are a bit more plain/basic looking than Sushi on Bloor makes them and the sushi bar area up front isn't as exciting as other places (like New Gen) where you can actually sit and watch things being made.