I like it, people say it's overdone now, but in reality (ie. outside of the forums) you still don't see it that often.
I think it sucks, generally. To me its just the typical polo/lupo "isn't my little car fun" thing to do.
then people like Fast car jumped on it... and I see it A LOT in 'real life' on all kinds of crap cars. Its the easy 'look at me' option, just like chalkboard bonnets, pedobear stickers and sh!t wheels painted pink.
The fact that you can buy books of the stuff from WHsmiths, or sheets of ready stickerbombed vinyl proves its already too popular!