Not a thing.
Hard to fault on a dollars-per-drive basis. Mine has travelled 55,000 km in 18 months and has never missed a beat. I regularly drive a mountainous road to the coast - brand new XR6 Falcons cannot keep pace through the bends, and the Astra can keep up with Lexus IS200's all the way. Very impressive for a car with no real sporting pretensions.
My only real complaint concerns the seats - they lack lumbar and lateral support, but are by no means uncomfortable. I also feel that the car is worthy of more than a Holden badge. This is nothing like a Commodore (in fact it runs all over them in the bends too...)
I also have a 2000 TS CD sedan while the car has power and handles really well owners should get thier 120,000 service done at 60,000-80,000 km before your timing belt snaps and you are without a car for two weeks while holden fixes it free. I was impressed with holden's co-operation to fix this expensive $4000.00 problem without delay, parts for these vehicles may need to be ordered.