Weather you paint or powerdercoat there will be prep to the metal. Powerdercoat is more durable than paint and they will bead blast there rims as part of the process then do color and usually some places do a clear over the powerdercoat as well different shops sometimes have a bit different recipe so to speak.
MY .02 is find soone who powdercoats wheels alot and will stand behind the work. even if it cost more. painted and powdercoated wheels look great. flaking wheels look like crap.
2013 ZL1 -sold
2013 Megacab 8" lift 38"mt's