I like how the car behaves on the highway. I think it is absolutely phenomenal how essentially an economy car can ride so smoothly, quietly, and securely at highway speeds. My mkIV was loud and all over the place on the road. The GTI has the feel of a much higher priced BMW. The car just hums along, like nothing is going on, and then you look down and see 80mph, I mean, like it's doing 40! Beautiful!
I can't speak for the handling yet, since I'm still breaking the car in and haven't given it a good toss on back roads.