i have to say i think the mk6 is a better car. I prefer the looks, the interior is better quality and the car is a lot more refined. The downside is i can't afford one, but if someone offered me a straight swap for my mk5 i'd snap their hands off in a shot. Although looks are subjective, and if we all liked the same thing the world would be a very strange place. i do however know they are having a few issues with the 210ps engine in the mk6...
There's not many cars i would swap my mk5 for, but a mk6 is one of them.