First, context. Keep in mind that everything we’re hearing about Windows 7 is way, way, early. Things can, and will change, and some of those changes have more to do with Microsoft’s partners and the OEMs than with just the OS. That said, word out of WinHEC is that battery life will be improved with Windows 7. Essentially what we’re hearing is that in the tests run there is somewhere in the neighborhood of an 11% to 15% savings over Vista.
Microsoft is touting a number of other advances over Vista including better boot up times, quicker times coming in and out of sleep and more, but again, keep things in context.