I've got five different friends with the current generation Golf GTI. They are awesome little cars for commuting. All are manuals except for the one friend with a flappy paddle. A few observations:
1) They all rattle. The one I'm in the most often has a nasty rattle from the rear seat belt spools. It's kind of inherent in the design. No real way to tighten it up. The other one has an exhaust (aftermarket) that is on the loud side so it's harder to hear the rattle
2) The two that are over 60,000 miles have had various electronic maldies. Window switches are the big one, but also intermittent Bluetooth connectivity. One of them is now having intermittent misfires. He had a shop replace the intake manifold (!) because of some secondary throttle butterflies (I'm guessing it's an emissions thing) that failed, which didn't solve the problem. Same guy is having some odd suspension noises with his that the dealer can't seem to figure out.
Other than those things, no real issues with them.