The R134a conversion is the way to go. There are several debate topics on R134a here, if you do a search.
You will here a lot of Opinionated suggestions
on how to convert by changing compressors, the oil is not compatible...bla bla bla
In the 100+ cars I have done, I used the kit from Autozone, Discount and Walmart now carries it! Work just fine follow with no long term problems. Just follow the directions and enjoy cool A/C