Fun, but also very frustrating as it is sort of half a flight simulator, only with the useful aspects of flight-sims missing (such as an artifical horizon on the HUD). Was glad I only rented it (would be worth picking up for a tenner, I guess, but not worth 30 or 40 quid).

Update I've taken the plunge and got it from ebay - much better value at 15 or 20 quid.
I was perhaps a bit harsh - the lack of proper flight-sim stuff does still rankle, but after a bit of practice with the controls and a lot of playing, I'm actually a bit of a fan now.
Finished off the adventure mode, which is satisfying, and might one day get around to unlocking all the special craft...

... but probably not!