In the Markham area, I've usually been going to the Highway 7 Moksha location, which I love. The Birchmount location has a lot of similarities, especially since the instructors appear to work at both locations. (See my Hwy 7 review!)
Anyway, the benefits are:
genuinely challenging classes, that are still accessible to beginners,
a bunch of variety of classes,
and great instruction.
This location is a bit more cramped though, and like all Mokshas, it's not all that cheap.