I've done mine twice. First time I bought duplicolor and lanka blob remover. Second time the more expensive dr. colorchip kit. Both are certainty bandaids but do a decent job of hiding the chip from 5'. Anything closer and you'll be disappointed.
I guess in general I'd say that a chip kit is worth the $50 or so, but if you're absolutely set on perfection you'll need a repaint. I think I ultimately went for chip kits because the paint on the g8 sucks so bad that I knew I'd just keep getting more, no matter how much I babied her.
check out autogeek for some good detailed advice.
2009.5 G8GT Premium OnyxRed Interior
corsa catback, vararam intake, cortex tune
custom audio, sharksfin, HIDs, LED Fogs, 20" MRR GT1's, Kayhan headunit