I still have R-12 and as stated before you can "hang meat inside".
I am still able to get 30# cans from Nassau for $135 ea. so I have a good supply and won't change in my NSX or my Preludes.
Being careful with the waste is important with both 12 and 134 but 134 is nearly as bad as 12, it just isn't advertised after all the BS that was raised to get rid of 12.
Freeze 12 is a never use product!! (sorry davidf) Some have heard of people working on a/c systems having them blow up in their faces, (smoking while doing the work usually) and this product is why. It is mearly an LP gas mixture, mainly comprised of LP gas. It does work as a coolant replacement but is highly volitile. DON"T
If you have a leak with either 12 or 134 it's important to find and repair the leak properly. Just adding more freon will delay an expensive and certain repair.
When the freon leaks, it is replaced with outside air. When that mixes with the remaining freon in the system it creates hydrochloric acid. Over time the system will corrode from the inside of all the components and piping, (aluminum) so you should properly evacuate and re-fill it with new freon to be sure the system has been evacuated of all non-freon gas once the leak has been repaired.
Cheers
nigel