The room is heated to 105 degrees and a humidifier brings it to 40% humidity. The mirrored room holds between 10 and 35 students (where I go), so you get between three and six feet of personal space for your mat. The teacher never wavers from "the dialogue" that they learned from Mr. Bikram and rarely cracks a smile. All of your personal belongings are in the back room except for a towel, mat, and water bottle. Nobody talks to each other, except in the locker room, and nobody modifies any of the poses. You sweat, grunt, and make your way through the same 26 postures every single class. Sweat drips all around, and the floor is carpeted!! The teacher knows everyone's names and is constantly mentioning who is doing it right and who can improve and how.
Despite- or is is because of- all of this, I love Bikram Yoga. Since I have been going, my back has stopped hurting 95% of the time (I was diagnosed with a slipped disc at L5/S1 recently), my shoulder and elbow never click any more, and I have more time in my day for the mundane (such as doing the dishes). My knees are much more mobile and in less pain (I have torn both ACLs and one MCL), and I can sit on my heels for the first time since I was a child. I can also garden with abandon, and carry my child whenever he needs (which is actually a lot-- around an hour or two per day still).
When I first started going earlier this year, I thought it was great and unlike any Yoga I had done previously. In Bikram's book, he explains that this method is the "real yoga" and actually makes a pretty good argument for this. The book is inspirational, and explains that if you do his yoga for 60 days straight, except Sundays, that your whole body will fast-track to a much better state. Then he says you can lay off to two to four days per week (or more if you want to get more of the benefits) and still retain all of the wellness that you have accumulated.
His book also explains that these 26 postures help the entire body, inside and out, as well as the mind and spirit. It sounds too good to be true, but I think he is onto something.
I go to a local studio near me called El Cerrito Yoga. There is another Berkeley studio called Funky Door Yoga that a girlfriend of mine attends and to which I have never been. There are studios all over the area and all over the world. All of the instructors are taught by Bikram himself, and he has them all say the same dialogue throughout the class. Again, despite (perhaps because of) this repetition and familiarity, I feel myself improving at each posture, slowly and surely. Each time the instructor says their shtick, I hear whatever I need that day and can improve on whatever my body is up to at that moment.
The next time I get pregnant, I am going to continue doing regular Bikram for the first trimester. Then his wife has created a set of poses you do during the regular class, which are shown on her DVD (which you can also buy cheaper if you buy it directly from Bikram). I loved doing yoga during my first pregnancy, and my practice is so different now, with Bikram Yoga, and I am looking forward to continuing it when the time comes.