I'm a 3c and I've been BKT'ing since April 2009. I've used so many brands it's insane but my favorite HANDS DOWN is QOD. With QOD Max (regular) I get bone straight hair which was fun at first but I started missing my curly hair.
I used QOD Max Organiq in Sept 2011 and I was very pleased. My hair was defrizzed, was still resistant to humidity but I was able to retain some curl. I only did 2-3 passes at about 400 degrees. This is my fav new treatment. I've been using QOD for about 2 years now and it can't be topped, imo.