I think I'd prefer spray painting because it would probably dry faster and get into every crevice.

 

I've heard the G2 is the best brush on kit, but I personally went with the Duplicolor kit. I got mine from NAPA auto parts for only like $14.99. Comes with brake cleaner, brush and paint for 4 wheel disc app. With brush on kits you don't have to tape anything off. Caliper paint is specially made just for this type of application so it settles very smooth and glossy, you will not see any brush marks. Do not apply heavily as this will increase your drying time. I jacked up the entire right side of my car and went front to back with light applications to give each wheel time to dry while still making progress. Took me about 2 hours with excellent results. You won't be dissapointed.

 

i painted mine red. looks real good when your done. i used a spray. and taking the caliper off makes it a lot easier