Given I've only had it one day so I can't say for sure but so far it beats any computer I or anyone else in the office has ever had. I got my macbook at 9:30 this morning and I had a hour meetting at noon. I got it and plugged it in and started loading apps on it. Meeting time came and the boss made it clear to take our power bricks because we would be in there for a while. Well...I didn't take mine and when I left the meeting I still had 59 minutes to spare.(4.5 hour meeting) Needless to say I'm impressed, did it last 8 hours, no but did it lasted at least 5 running full time with wireless, browsing and installing. Has any computer ever done that before..no. Another co-worker has a netbook and his battery lasts for about 4.5 hours, this giant 17" macbook dual-core 7200RPM HD last longer than his netbook. To sum up, great machine and great battery life. Side note. Can you swap the battery in 30 seconds...No, but we knew this. It took me under 15 minutes to change out the HD today so to change the battery in this thing would probably take anywhere from 5-8 minutes and even less if you didn't want to put back all eight screws. The battery is changeable if you want to carry a screw driver with you.