AYCE Sushi on Yonge St between Dundas and Bloor
Oh my god NOOOO! the Springsushi (one word) at Yonge Dundas is the place to BE, not to EAT. Their gimmick is the menu is on a tablet, you scroll through it and check off the items and give the tablet to the server who will send in the order. I had a bento box which had sushi, and had to ask for wasabi and ginger. The rice in the sushi was hardly seasoned. I couldn't finish the grilled salmon so asked for it to go. The server said did you want to take that (indicating the leftover tempura) too? I said no. The takeout box never appeared and when I asked they found the food was thrown out! They wanted to give me a $10 voucher, but after waiting for 10 more minutes I decided I don't want to go back anyways so we left.
Natural Sushi is a place I wouldn't go back to either, though last time I want was years ago.
I think that you will be hard-pressed to find a "good" AYCE place on Yonge street, but if you're looking just for any basic AYCE within that stretch of Yonge, here's a brief list:
Natural Japanese Sushi - 714 Yonge
Spring Rolls - 693 Yonge
Takumi Sushi Restaurant - 484 Yonge
Spring Sushi - right off Yonge in the old Woo Restaurant - 10 Dundas St. East