I don't know about everyone, its working really well right now though.
despite how common it is, its really hard to teach. Two years ago I was "wrestling" (I was getting killed so badly that term might not be appropriate) an AA who isn't even known as a collar tie guy and his felt like an iron lego snapping onto my head. I had people on my head maybe a million times and never felt anything like it.
It wasn't more than ten years ago that I heard a lot of prominent coaches be very wary about letting some athletes touch the head at all, because there are a lot of very effective counters, but PSU has definitively shown that the pros outweigh that danger...