I have to say that I LOVE bikram yoga and encourage you to give it a try. At my current weight/ age, high impact exercise is quite uncomfortable. Even standard yoga was too hard because in many poses I was unable to support my body weight. In bikram there is a specific set of poses and I found them easily adaptable to all fitness levels. The room is heated to 105 degrees - you sweat buckets!
Personally for me WL was moderate, I lost ~10 lbs in 6 weeks and I was going 2-3 times a week. The big bonus for me was how I felt. I have problems with depression/fatigue and while I was doing bikram regularly my symptoms improved dramatically. I had tons of energy, increased mental clarity, I felt AMAZING. And though I had been losing weight consistently for more than 6 mos, I got the most compliments from family/friends/coworkers during that time - I felt as if I radiated health
I had to take a break unfortunately because finances are tight and it is expensive

I hope you give it a try and let us know what you think. I do other forms of exercise, walking/hiking, fitness videos because I
should but bikram was one of the few activities that I actually looked forward to and I hope you have a similar experience.