Golf 5 vs Audi A3 8P

I am looking to buy my first car and I need some advice. I'm specifically looking at the 1.9 TDI BKC models of both cars. The A3 is just a bit more expensive than the Golf in my country. Is the A3 really a class above the Golf? How do they compare in terms of quality and reliability? Is the A3 more expensive to maintain? What are the problems of both cars?