My brother taught Barkan Method Thursday night and Sue taught Bikram Friday morning, so in a little over 12 hours I got a good comparison. Without going into the whole Barkan learned from Bikram and then branched off to modify his own way of teaching Hatha Hot Yoga, lets say they both are tough in their own ways.
Barkan, at least they way John teaches, is fast paced and it moves and grooves. You are flowing through postures into other postures and then holding. It is cardio intense at points. It also has more upper-body weight bearing postures and inverted (or inverting into your front) moves.
Bikram is all about holding, squeezing, and pressing deeper into postures. You heat up from the holding and the squeezing. At points the air is limited because your throat is compressed, at other times you are breathing deep into your toes. While less of a flow, I enjoy adjusting into the postures and trying to get there.
The pools of sweat in Barkan are on your towel, around your towel and everywhere. In Bikram, they are mostly on your towel and mat, under you. In both you need to hydrate and do the best you are able.
I did a lot of Savasana in both classes. My knee was killing me so the one legged postures and the lock your knee ones (and anything that had me kneeling) was unbearable if I pushed. So I went for a chiropractic adjustment (at my dear wonderful yogi brother's office) and I now feel freaking fantastic.
The absence of pain after he worked on my knee was immediate. I feel a HUGE change. I need to get regular adjustments again. Sometimes you don't even realize you are in pain until it is gone. My neck and shoulders have been bothering me for weeks, crampy and annoying, and I felt such a breath of air when he gave me a good adjustment. I am ready to put my new knee to the test in class in the morning!