I hate to put my name to this but I have watched this discussion at many different technical levels. Anyone putting his name on quality work will hide their head on this subject. With that said, I do have a positive experience. My tightwad German partner heard me discussing the scientific principles on this subject and decided to try it on his 93 400SE. It was leaking a pound a month last summer and he put the stuff in and has yet to add any refrigerant. I hate to say, how well it it working.
We have not done this on a customers car and probably won't unless they bring up the subject. There is numerous questions about what the stuff will do. The way the product works I know a little about. Interestingly enough the basic chemical is manufacturered here in Gainesville and there has been two toxic spills at the facility that have had wide spread media review. The chemical a hydrate of silicon I think forms silicon dioxide crystals in the presence of water vapor. Thus in the spills there were huge white clouds of sand so to speak. This is what plugs the hole as the product reaches the moisture in the air. I would say that systems contaminated with moisture would really take a beating.
It will never go in any car I own.
Bosch Master, ASE Master, L1
33 years MB technician