It's not about which is better, it's about what you want, proper set up and tuning from a Auto gov you can achieve the same results.
Unlimited rpms with a AG governor or fight defueling issues with a auto gov.
That used to be the case but I know multiple auto gov trucks turning 5k+ with no defueling issues.
It all comes back to the shop, do not buy cheap just because it says 13mm.
-Clinton