I like BM and P57 and I would not want to get rid of these or have to choose between them.
I like BM for the days I just want a quiet relaxing workout with a soothing voice. BM is easy for me to pull out and just do it. There's also a less dread factor to these for me. I know she gets really tough in the accelerated, but by that time I'm already in full swing of the workout. I just say to myself it's only the thigh part that I have to get through and it's done. But she tricks me everytime.
I've forgotten about the other stuff she has in store for me in the rest of the workout.
Then there are the days I want noise or something that's going to get me going. Once I pop in the dvd, the starting music has me already going. P57 is great for those days. Of course, again I start out thinking that it's not going to be so bad, but it gets me burning, too. Also, I think P57 get me more sweaty.