My experience has been that paint is superior. I work and play around modified vehicles all the time, what I see people spending a LOT of money on professional powder coating, only to have it go south down the road. The complaints I hear and see are color fade, and peeling. It seems one nick down to the metal and you’re screwed. Not true with good paint and the correct prep which the powder coat had done.
I paint my engines, suspension, and body with good paint. No problems, that is unless I want to remove it. It won’t peel off like powder coat. Paint has a bad rap because people don’t use the good stuff. Eg; on my last valve job the tech told me my heads were the first ever to survive the hot tank cleaning with the paint intact.
Maybe powder coating has the same bad rap? Or maybe the good stuff has only recently come out?

Even if it were superior, I would still use paint because it’s substantially cheaper, can be done at home, and damage repair is easy, and it’s more than good enough.

PS: I do paint certain internal engine parts. It works perfectly, just don't buy your paint from WalMart!