Problem with powder-coating is finding a good powder-coating shop!!! I've had wheels done by three different shops (from 13"x4" Metro wheels to 16.5" Ford 3/4-ton 8-lugs to a brand-new NOS Chevy wheel), and the powder coating looked great on the finished product, that is, until you actually USED the wheels on the street!!! The wheels started to rust in the seam where the wheel center and the wheel rim meet on EVERY ONE, after only three-four months, on average!!! I've NEVER had that problem on a painted wheel!
I'll stick to painting when it comes to wheels!!!