I just picked up my macbook this week. I used to have the 12" PB and loved it and so far this is making me even happier! I left my house around 5pm tonight and got home around 9pm. When I left, there was about 30% battery and I left it on to let it drain. I came home, expecting it to be asleep, but instead it was completely turned off. I know that it can only sleep for a bit until the reserve battery power is used up, but it should be longer than 3-4 hours right? What are your guys' experience with this? I could swear my old PB would sleep for a day or two!