I started going to Yoga at Heavens after buying a 25 pack of yoga classes for $20.
My roommate and I now go 3 days a week. The variety of Yoga classes they offer is great, the only problem is that the instructors don't seem to be static. Our favourite Friday night class has changed instructors 3 times in 3 weeks.
If you didn't get a deal to buy your passes I find it incredibly expensive. Our classes are great, but you do have to get there about 30 minutes before to insure your place as it is very popular.
While I cannot say enough about how great the instructors are, I don't feel the same way about the staff at the front desk. They allow people to call in and put their names on the sign up sheet, and turn people away who actually arrive at the studio ahead of time. They play favourites.
Also the layout doesn't work so well. The area to wait for the next class to start is directly in front of the studio glass doors, so when you are at the end of a class attempting to relax into you Savasana you can hear the noisy talking and chatter from those who are waiting for the next class to start.