my expericnes is limited.... but the frame I painted with auto paint has had pretty durable paint, the paing with rattle cans not durable at al.

this is what i did (after much reasearch on forums)

stripped frame chemically and then used scotchbrite pad

gloves on

clean frame with acetone

used acid etch primer

dried to recoate time

used high build up primer

light sand

used 3-4 thin coast color using a preval (forget paint brand, but is was automotive, hit it with reducer and start painting) I allowe enought time so that I could get all the coats on as soon as recoat dry time was complete.

then 4-5 coasts of cataliyzed clear... again careful with recoat times.

this is on my son's fixie.....so far very durable. One big chip but that was not a paint failure.

overall i think bike paint gets much more abused thad does car paint...so it could the there needs to be lower expectations as to bike paint durability?