Always liked yellow cars, I especially like the metallic yellow Peugeot offer on the likes of the new 208, and the "speed yellow" Porsche offer too. My mum used to say green was unlucky, but me and two other friends all had yellow cars for our first cars, and all three were crashed within 6 months haha.
I'm no expert, but I think alot depends on the quality of the paint, and whether it has a clear coat on top, and how good the UV resistant properties in that clear coat are. In times gone by, all paint finishes were water based and would oxidise after a few years giving them a satin finish. Modern Cars use a few mil of clear coat which protects the coloured paint from fading/scratches etc.