I think the value in any workout is more than the calorie burn and anything measuring burn is giving an estimate. According to my hrm, I burned about 250-350 for p57 classic (v.1), express was more intense and had a higher heart rate but is 1/2 the length so not as high a total burn. My hr doesn't get that high so I never get a very high burn so I would think some people might get 500 or so for the hour. Not bad. I did try to mod up and usd as heavy weights as I could, did some of the moves without the barre to test balance, did some extra arm moves on occasion, went low when she said, did as many strait legged push-ups as I could, etc. I haven't worn my hrm for v.2 though. Booty Barre "burns" similar for me as does Cardio Barre. But I don't fully do Booty Barre as I don't do the weights part (I've been into other strength since I had BB) so it might not be a fair comparison. A lot of the fast paced barre do emphasize their calorie burn so that is perhaps a fair point. But I agree that is the least of their benefits. I admit I don't care for some of the marketing talk some barre instructors use as some of it sounds like they are spreading misinformation about long muscles, spot reducing, etc. However, I do feel I get good fitness and aesthetic gains from barre and a lot of others do as well so it isn't all bad.