If the purpose of this thread is just to find out who is using superthrive and how they use it (as opposed to solving the eternal riddle as to whether it actually has any benefits), I'll weigh in. I use it often when repotting, especially for nursery stock or collected stock that has undergone major root reduction. Also when a tree is stressed. I just put a few drops in a gallon of water. I don't use it as a part of my regular watering routine.
So why do I use it, since I've never seen any actual scientific evidence that it works?
1) Bill Valavanis recommends it (and I'm pretty sure he applies it every time he fertilizes, hopefully he'll correct me if I'm wrong). He has pretty good, healthy trees.
2) Other local club members whose work I respect also use it.
3) I found a very cheap bottle at an end of season sale a couple of years ago and figured why not give it a try.
Not sure what I'll do when the bottle runs out.
Chris