Re: How much more would 500mAh give?
I have a conspiracy theory. The Moto 360 battery is rated at 300mah and claimed at 320mah. I'm assuming they tune the voltage so it get the same battery life (Watt hour) as a 300mah running at slightly higher voltages, so they can claim the battery to be 320mAh in paper, I'm not an engineer so I could be wrong. And this is despite what the spoke person said about mislabeling the battery. The Moto G 2014 battery is the exact same as the 2013 version. It is possible that the Moto X 2014 battery is the same one as the original. Well it doesn't matter anyway, because it's only 100mAh difference.
I think 2800mAh is a stretch for the phone already being 10mm at it's thickest point. They could fit a 2800mah battery in it and not increase the thickness, but they would have to make the back of the phone flat and not curvy.
I would say with the extra 500mAh, it should give at least 1hours of screen on time more.
I definitely see a sizable decrease in battery life for my Moto G 2014 from the previous version. One hour less screen on time infact. I'm not sure right now, with knowing this and the original X will get most of the features of the new one, maybe I could be happy sticking with the original X.