I started with the yoga from the Cyclo Core series by Graham Street. About 6 months after that I ventured into a level 1 class at my gym. My gym is a full service club, that is not one of those "huge" gyms that advertise on TV. It's been around for 50 years, starting as a tennis and swim club. They have 5 classes a week, so it's not like it's a big part of the program. I have found that I was glad I had it done it on my own before I went to class. The instructors are all very good, some are 500 hr. certified and others 250 hour, who are working on the 500. They all have taught for years. At first, I was put off by the "spiritual" part and the "noises" some of the participants made. But, I got used to it and now I can say, it really helped me through my difficult months last year with the fibromyalgia. I also have scoliosis and many other sports injuries and it just has taught me to stretch and relax! I never do the advanced classes, doubt I could handle those poses, but I have improved a lot.
I never thought that anything could have me totally relaxed and practically sleeping on the floor in front of others, but it did happen.
+1 on the Bikrahm yoga. The guy who started it has a studio near the university I go to and some of the other students go. I think I would faint doing poses in that heat.