I painted the rims on my race bike with Duplicolor aluminum wheel paint from Canadian Tire. Total cost about $15 for a can of the base coat and a can of the clear coat, which did several rims and other parts. I used it to fix up a set of aluminum rims for an old car, also, with the same cans, and I've also used it to paint various parts that started out as unpainted aluminum but which ended up looking iffy due to corrosion over the years. The painted aluminum parts certainly look better than aluminum corrosion. Cost per rim amortized over 4 car rims and 4 bike rims plus upper triple clamp plus a few sets of fork lowers is pretty low ...
It stands up reasonably well for what it is. If there is a chip (and they will chip!) I can fix it easily by myself. Can't do that with powdercoat. Seems reasonably resistant to brake dust and general road grime, and chain lube wipes off pretty easily.
It is only available in a limited number of colours - basically, black, white, and a few shades of silver. I picked metallic silver that is close to natural aluminum ... because WHEN there is a chip, it looks close to the same as the underlying aluminum. And it matches up OK with the natural-aluminum frame on my race bike.
For this application, I'd do the same thing again - and only in the natural-aluminum metallic silver finish (because chips and scratches won't be very visible). If you want something outside the limited range of colours available in the aluminum wheel paint, it is not an option. I wouldn't suggest using normal automotive base/clear ... doesn't seem tough enough, not as easily repairable WHEN you get a scratch in it. For anything other than natural-aluminum metallic silver ... powdercoat them and be careful during tire changes.
Powdercoating does not lend itself to true metallic or pearl finishes. But are you sure you really want metallic or pearl-white on your wheels? White wheels look miserable except within 5 minutes of being meticulously cleaned. Yet another advantage of metallic silver ...
