Without a doubt best looking phone ever and its sooo smooth!! My only complaining is that after updating to lollipop battery life went from 3 full days to 2 days. Its not bad at all to consider i had to charge my old phones every day but used to be better on 4.4.4
One thing to note, it records videos and sound better then my £1000 canon digital camera.
What a terrible UI on the HTC One M8 despite it's great looks and performance. Back to Samsung for me, so a better UI, but an ugly looking phone. No options on the HTC One M8 to change the background colour on the built in Mail app or in Phone Book to black with white text. Something that would be useful for visually impaired users.