Of course I haven't used it. It is a violation of federal law to put it in an automobile or truck. I would also note that is against the law in some states to use ANY flammable refrigerants in automobiles including the states of Virginia and Texas.
It is also a violation of the clean air act to vent ANY refrigerant into the atmosphere, even if it's nothing more than the gas in a Bic lighter.
There are over a dozen safe, legal, and approved replacements for R-12 in a car, what is the upside to it?
http://www.epa.gov/Ozone/snap/refrigerants/hc-12a.html
If one of these cars gets sold and the next guy doesn't understand the difference, and takes the car somewhere to get the A/C serviced, the least that will happen is you will contaminate the gas in their recovery machine (I've lost over $1,000 in 12 & 134 that way)
Or worse the wrong type of leak detector will set the car on fire, or the recovery machine will explode. But what the heck, you saved $10. Not to mention if you have an engine fire the car won't just burn, it stands a good chance of exploding from the compressed propane that shouldn't have been there in the first place. I'm sure the cop or firefighter that gets killed or maimed will understand, I mean $10 whole dollars!
Damn right I'm pi$$ed. IT IS ILLEGAL TO USE IN A CAR FOR GOOD REASON.