Yoga is yoga, My research found that the unsually high burn estimates for Bikram only come form Bikram sites. Some support this by heart rate but, unfortunately a heart rate monitor is just about useless for Bikram. First it does not meet the underlying assumtions of the math behind the estimates and the heat of the room will force the heart very high for cooling not for bruning calories.
Last time I entered a discussion on this the expert a long term Bikram Yoga instructor basicly called me "Fat and Stupid" for talking about my research and asking hime to support his contension that Bikram burns more calories per hour than running.
This does not mean that he represents all Bikram Yoga professionals, it does suggest that he did not have better arguements to support his contention that Bikram burned more than other yoga forms