Regarding battery life, I will see today at work how long it lasts before a charge. It will be getting some heavy demo usage though.

I have noticed that the battery % does seem accurate. On my N9 one I was below 30% I needed to be no further than one hour from a charger. There is none of the old 20% to 4% drop in a matter of minutes.

In Helsinki when I was getting to know the device I got to 3% battery and it did not do the N9 three knocks of impending doom. I have not yet use it to exhaustion so not sure how much notice you get of shut down.

As for screen brightness, IMHO it is like the N9 on the normal setting. It cannot match the OLED Vivid setting.