Apple did two things simultaneously that are usually contradictory; they lowered the price of their entire MacBook Pro line while at the same time bumping up the specs. The 15-inch version now starts at $1699 and caps out at $2299, down from $1999 and $2499. What's even nicer is that the 13-inch MacBook—which previously didn't have a Firewire slot or a "nicer" screen—got absorbed into the MacBook Pro family and is now virtually indistinguishable from the rest of the Pro line.Much more after the link. Below is a graph showing how the battery life tested out.
Two other things changed on the build that make the Pros more appealing to regular consumers. The replaceable battery has been swapped for the same type of lithium-polymer internal battery previously found in the 17-inch MacBook Pro, which boosts battery life at the expense of not being able to be changed out in the field. This, for the large majority of people, is a good thing. The batteries last 1000 charge cycles, which at 200/cycles a year, would last you five years. Even if you go through one charge cycle every day, you'll still make it about three years before you need to take Apple up on the $129 replacement. (The $129 includes shipping, labor and disposal of the old battery.)
In our test, the 13-inch MacBook Pro got 3:31 of battery compared to the 3:46 of the 15-inch MacBook Pro. We used the same metrics as the previous MacBook Pro test—medium brightness, Wi-Fi on, keyboard backlight on low, H.264 movie—and got about an hour more on each machine. That's a pretty incredible jump just from a change (non-user replaceable battery) that most people won't notice.
I'm guessing you could get more real world usage out of it if you tweaked some of the settings. One of my classmates here in Santa Fe has one of the new 17-inch MacBook Pros and he says he gets about 9-10 hours out of it if he turns off wi-fi and let's the screen power-off after a few minutes of non-use. Not bad at all...