Not the best all you can eat sushi I've had, and not the worst!
There's quite a selection (vegetarian and non-vegetarian) and the food is good! Definitely not bland like some other all you can eat sushi places I've been to, but I also can't say it compares to some of the better ones. The first time I went I ordered some weird vegetarian "specialty roll" which I couldn't finish because there was ginger and some other things inside it which I could not stand (but I will blame this on poor ordering choice), however the second time I went I ordered the right things and was much more satisfied. I seriously have no idea where to eat AYCE sushi in the more south-eastern parts of Markham, but compared to the other place I've been to somewhat near here (Mikado Sushi Robata), Sushi on 7 is amazing.
I found the service to be alright and I don't have any complaints when it comes to that. My whole group printed off 10% coupons from RedFlagDeals and they were all honoured. The atmosphere is not the best as the place is always busy and quite small, but this isn't very different from most all you can eat sushi restaurants.
I'm really torn between 3 and 4 stars for this restaurant, but I think it may be a bit too mediocre for a 4-star. Overall, I would recommend this place if it's close by and you're craving sushi... but it's not really worth going out of your way for!