Not surprised. Apple can optimize thier software for their tightly controlled hardware. You can actually optimize Ubuntu for a decent gain in efficiency. With a basic script, I can get my ProBook down to 10W or so at idle, with 4-5 hours of battery. Interestingly, I can also get OSX on it, and it can only do 3 hours. Apple just doesn't have to optimize OSX for random hardware like Windows and Linux do.