I purchased a 2008 XR model with very low mileage early in 2009. So far I haven't came across any issues with this car. It's powerful enough for urban driving, and gets decent enough mileage proving you don't drive the snot out of it. The best economy reading I managed to achieve with this car was 7.1L/100km on a 600km round trip.
However I am not normally concerned with fuel ecnonomy numbers while driving
and for the last 10,000kms I put on the car I achieved an average of 8.7L/100km (70% city/30% highway). This is on an automatic equipped 3dr model.
It has excellent highway manners, extremely stable and quiet on highway speeds (easy to go over the limit with this car when not paying attention/not using cruise control). The engine doesn't drone, and the standard lighting is excellent at night. The Astra also holds a ton of supplies once you drop the rear seats and actually take advantage of the hatchback design.
Overall compared to my previous car (2005 CTS) this is a very competent, well equipped vehicle. Considering I normally hate small cars, I really can't complain about this car. Everything just fits together as it should providing you take the time to learn the car and figure out its little euro quirks.
On a side note: The brakes don't squeal, I do not have issues with brake dust. Plus that 'faulty" fuel cap issue is not really a problem. The only time that shows up with this car is when the owner (or gas station attendant) is too lazy to close the gas cap with a full turn.