I attended a yoga class at the south location of Yoga Yoga a few months ago and was very dissapointed with my results. The class was very impersonal and felt like the teacher was just shouting out directions from a book. Also, the room was unclean with a bad stinch. I even tried returning to the studio a few weeks later, only to discover the same results.
Pros: multiple locations
Cons: feels like a chain