I've done 2 DIY bike paint jobs. It's a real PITA if you're not patient. I don't know if I didn't wait enough between coats or the BBQ paint I used was crappy but seriously the paint chipped or spread just by looking at it. I didn't mind since the bike was nothing special.

But for a bike you care more about Marinoni does a decent job for 150$. One week turn around. I can show pics if you want,