I converted over to r134a several years back, as I had an AC leak and r12 wasn't legally available in my county in SoCal. It seems to cool as much as I want on even 95 degree/80% humidity days. However, it also seems to take a little longer to get the temp down than did the r12. All in all, no complaints so far.
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E