Hmmm tough call really, as an M8 owner I can't see any point to me "upgrading" the only thing this offers for me is a greatly enhanced camera, given most of my shots are purely intended to capture the mood or feeling of a moment and not the minutiae of detail in it I'm nonplussed about having a better camera for £500.
I'd have liked more of a design refresh than is currently being shown but I loved the M8 in terms of layout and looks, power button at the top wasn't an issue as I don't have ladies hands and there's double tap to wake.
If I was to have to go for another mobile this year it'd be the note 4 but as I don't I'll stick with my current M8 and see what next year or Q4 of 2015 brings.