Watch this and it speaks volumes....unless you want an AMOLED screen you're best off sticking to the M8.
Camera, lack of on-screen buttons, and general size also play into it.
If the M8 was a little smaller, and had a better camera (doesn't have to be fantastic, just able to compete all round) then I'd have got it without any question. But those two things (mainly the camera) were just enough to completely rule it out for me, and it seems a fair few others as well.
It's a shame, because other than that, HTC have made a fantastic phone there. The design is lovely, finally a microSD as well, good battery life, and the performance overall is probably the best around.