6 hours is not bad at all. (on Linux!) :) I'd be pretty happy with that.
I installed Ubuntu 14.x and i3 window manager. I have dual boot with original Windows install and power use is comparable between Windows and Linux. It's a pleasure to use. Only power management tweak I made in Ubuntu was to install the TLP power management tool and (I think) make simple change from its defaults: http://linrunner.de/en/tlp/tlp.html
Performance wise it's very nice. Screen is decent, too. My only complaint is the that the keyboard has a bunch of non-full size keys. End and Insert are on a single key. Someone should be shot for that.