I seem to be having very frequent hanging on my Macbook air, and see the spinning colour wheel way too often. I am a fast user and typically have a few windows open apart from my IDE and local server, but not much else. I only occasionally use known memory hogs such as Photoshop, so I don't attribute this to them. I'm on OS X 10.8.3 and processor 2Ghz i7 with 8GB ram, one of the best models, so I was expecting a smoother performance. Anything I should be on the lookout for?