Firstly, powder coating is a process like electroplating and not a product.
So you can get cheap vinal powder coating like on thoes cheap cloths airers or outdoor funrature that breaks down in less than 6 months.
Or you can get the metallic oxide powder coating they put on fuel boosters of rockets and anything in between including full vitrious baked enamel as on your bath tub.
Secondly again I go for POR 15 on hubs.
The chassis coat will never peel flake or rub off provided you remember to top coat it and do the preperation properly.
So it is a once ever job, never to be done again.