I had one installed on my up! white, it breaks up the contrast between the dark rear window and the white paint. And yes, it does add a bit of class to the back side. Funny they're not standard on the up! white as they do have all the other extra chrome trim partsanyway.
I hate chrome on cars. Chrome was a posh metal treatment that was used to stop rust on steel. Most chrome nowadays appears to be plastic. If you must have daft metal bits to adorn your car, get them made out of the correct metal, which is stainless steel.
You may have guessed that chromium plating is not my favourite stuff, but I would defend your right to put whatever on your car. Even pink nissan convertibles. (Having said that A large expensive peigeoooot covertible went passsed me yesterday and it was critically evil looking.)