I've used it the past seven years myself and the past six with my team. I had problems for years with tight hamstrings and hips even though I stretched religiously. Three weeks after starting with Active Isolated Stretching, my problems disappeared and my stride was suddenly able to open up and really move. Had I known about that in college (5-6 years before), I could have had a very different career.
Also, in the first year I was head coach, we used traditional static stretching. I had eight muscle injuries from a team of 35 girls. The next five years, we used Active Isolated Stretching, averaged 50 girls per year, and had six muscle injuries total during that time. Five of them were with girls that spent more time gossiping than actually stretching.
I check out different stretching techniques all the time. If I ever find a better one, I'll switch. However, for six years now, I haven't found anything better.