I wasn't sure if the mix of r12 and 134 caused a reaction. However I have read that r12 and moisture causes an acidic reaction and when average people try to convert there own system they do not have the right equipment to prevent the moisture from getting into the system and causing problems. This is another reason converted systems fail.

freeze12 (and es12...diff brands same type of product) is not at all 134. I guess that you could say that because 134 is a synthetic and freeze12 is part synthetic that freeze12 is part 134 however I do not know if the synthetic component is the same. Check out this site for a technical explanation of what these new refrigerants are. http://autorefrigerants.com/Envirotechnical.htm
I would hope you would not condem a new product just because you are not familiar with it. I have seen posts of others that use and recommend these products and that is what caused me to check them out as I was not familiar with them either and I did not want to talk about something when I had no idea what it was. I do not personally have any experience with these products but I like what I have read and until I read or hear something bad that can be backed up I will have to give them the benifit of the doubt.