Mechcozmo - I'm a longtime mac-user (since 85!) so I don't mean to sound like I'm permanently disappointed in the brand for this alone. When I first got thie PB, the battery life was 2.5-3 hours tops, even with all the settings lowered. I complained about it, even sent it back for tests, and they told me that's just the way it was. So, I had to rush between classes to recharge and other minor hassles, but I lived. This battery eventually stopped taking a charge, so I had to replace it. To me, replacing a battery every 2 yrs (even though this one last only 20 months) is not a big deal. Batteries have a shelf life, I understand that.
The new battery got double the battery life of the original. I couldn't believe it. I had an all day seminar and the battery last 6 hours with only word running. So why did they lie to me the first time? I called about it, they had no explanation. Since then, the battery is now 2 months old and back to the 2.5-3 hour battery life maximum. My roommate has had the newer PB for 7 months now and gets a consistent 4 hours.
They advertised 5 hours, but it only gets that as an overpriced paperweight, not at normal use. Shady.
Again, I say--- I expect better.