The only problem I have seen with painted on graphics is that they look great at first, but if you ever get a scratch or nick in them, then they don't look so hot. We have quite a few boats come thru here with painted registration numbers on the front of the boat, and many of them are scratched or smeared from a boat bumper hanging over the side of the boat or what not.
If you do get them painted, don't let them get scratched or smeared!
McFly
www.waterskiboatsdallas.com