I had my worst battery day yesterday. I was away from home for all but the last four hours (out of 17 unplugged) so off WiFi most of the day. I navigated for 90 minutes, mostly through rural Maine and NH, without plugging in. (The phone was slightly warm when I was done; certainly not blistering hot, like all previous Android phones were when navigating.) I then was on a scenic train ride for 5.5 hours, with about 4 hours of that without signal, with the phone searching.
When I arrived after 90 minutes of navigation, the phone was at 79% battery left. When the train ride was halfway through, after two plus hours of searching for signal, it had 59% battery left.
I should note that on the return train ride, I kept checking to see if I had a signal yet, and never did. Finally, when I passed a ski area, where I knew there should be at least some signal, I still had none; I flipped the phone to airplane mode, then quickly toggled airplane mode off, and I had a signal right away. I think that there may be an issue with the phone regaining a signal after it has lost it for a while, because my wife was able to text with her feature phone while the Maxx supposedly had no signal.
Anyway, I then drove home (though without navigating) for 2.5 hours, half of that through rural NH, where I am sure the cell service was at least a little spotty. I then caught up with messages, twitter feed, and Facebook and Google+ when I got home (on WiFi). I went to bed after 17 hours off power with 29% battery life left. I had 3 hours screen on time by the time I plugged in at bedtime.
I think this about the worst my phone will face. I am a bit concerned about no regaining the signal without toggling airplane mode, but it's great to know that I can get through a day, no matter what, without a power source. I never could have done this with any of my other Android phones (though, to be fair, I could have swapped batteries, or charged while I was driving home, etc.)