The 2 Bikram studios I tried were carpeted. They struck me as ideal fungal incubators. Stanky too. To be certified as Bikram studios (not just "hot yoga") the instructors and the facility must conform precisely to Bikram's standards. I am pretty sure the carpet is part of that.

Another aspect of Bikram is that every session is the same, word for word. If you take the class, listen for the words "Japanese ham sandwich." (Maybe it changes over a longer period, but in the dozen or two classes I took the words never changed.) Bikram insists that his poses, done his way, in his prescribed order, constitute the only REAL yoga available to Westerners. I do find his routine to be a comprehensive and enjoyable one, but I prefer to mix things up.

I find a studio heated into the 80's plenty hot enough. The Bikram studios I tried were well over 100, sometimes over 110. That is hot, even for a guy raised in Phoenix.

A lot of people love Bikram, so I am glad it is there for them. There are many styles of yoga. I suggest trying a few to see what you like. Personally I like Anusara yoga.

I have practiced yoga for 35 years and have come to prefer Gentle classes, at a slower pace, which allow me to move into and out of poses with attention to the inner and outer experience. I have a competitive nature, and if I take a more advanced class I find myself pushing it to the point of injury.

You will find a lot of discussion of Bikram and his yoga over at Yoga.com.