I had a Polo 6n. Great car, really good to drive and the seats were very comfy and supportive even on long journeys.
It was a Dragon Green 1.4 8v, so only 75bhp I think, but plenty nippy round town and even on the motorways.
It's true about the gearbox though, ours went. It started with jumping out of 5th gear every so often, then eventually it wouldn't go into 5th at all. Apparently 5th gear is the first one to show signs of a dying box. Be warned, a brand new box from VW was £1k, or around £700 from Mr Clutch.
I'm told that these gear boxes are the same ones as the lower end Mk3 Golf ones, which suffer the same problems.