Koolkar's right. There's a 10% difference in cooling capacity. R12 is still available, and the price seems to have stabilized. Importation of R12 is allowed, but companies can only import a set amount each year.
Some of the new refrigerants show promise. Search for "alternative refrigerants".
I'm getting ready to get the a/c on my 69 going, and still have a few cans of R-12 left.
