I would like to add to the above "downside" of this stuff the fact that when using it, most people do not label the system as having this "refrigerant" and they do not change the fittings. This sets up a situation where it is recovered into a vessel of R12. The result is that the other recovered R12 in the vessel is now unrecyclable.
For the sake of those of us who wish to recycle as much R12 as possible, please don't use this stuff.
Additionally, this is real snake oil sales. You could put propane in the system and it will work as well as this "product" with a fancy name. I don't know what they charge for it, but propane is around a $1.50 per GALLON. There are probably at least five pounds in a gallon, but they are probably charging $5 a pound for something that usually costs only about $.25 per pound. Sounds profitable to me.