I did Bikram for about three months, twice a week, at a place close to home.
Bikram is done in a room heated to over 40 degrees. Every session lasts 90 minutes. Every session does the same set of postures in exactly the same sequence. Officially the instructor is supposed to read and not deviate from a script developed by the founder, Bikram Choudry, though fortunately my instructors tried to elaborate a bit more when necessary and give some individual assistance.
I think Bikram would argue that this stops less skilled people muddying his teaching for the masses ... but IMO the result is a dumbing down to the lowest common denominator. Parallels with McDonalds.
The heat feels good to stretch in and there are a lot of back bends which I am weak at, but after spending 90 minutes in the heat I found it tends to space you out a lot and tires you - some days worse than others. Forget doing a Bikram session and a solid Jiu Jitsu session on the same day at my age. 90 minutes of a class is a bit long for me - not endurance wise, just too long. I'd prefer an hour class for something like that.
There's only very basic breathwork, with no real explanation of its purpose.
If you read up on the founder, Bikram, he comes across as a sexist sleazebag with questionable ethics. He doesn't look particularly toned. The owner of the school I went to had spent a lot of time with him and various other yoga gurus in India and knew his stuff. I found the owner quite likeable, but he gave this speech in one class about how he's just got back from hanging out with Bikram in India and segued into a short lecture on obedience which I found too much of a moral and philosophical bridge to cross. A bit too cultish.
I find Jiu Jitsu to be a really social activity, I'm always running into guys and girls I've met somewhere because of Jiu Jitsu, but while a couple of female yogis talked to me after my first class, and I talked small talk with guys in the changerooms, on the whole people just hung with their friends and there was no real sense of a club or community, which there always is at any decent BJJ school.
As for any spiritual, transcendental or self-improvement aspects of Bikram, I reckon BJJ provides all that Bikram does and much more if you're open to it. Look at what people like Rickson and John Danaher do with it.
Steve Maxwell's stuff is SO much better for Jiu Jitsu people than this. By a ridiculous margin.