HTC One Pros: Lovely screen, Front facing stereo speakers (they are lovely), Snapdragon 600, Good at low light pictures, Premium feel
Xperia Z Pros: Water proof and Dust proof, Sturdy build quality
HTC One cons: No MicroSD Slot,Non removable battery
Xperia Z cons: The screen has awful viewing angles, Processor isn't as strong as HTC One, Non removable battery, Camera is good in day shots but not that good in dark shots.
To conclude I'd say the HTC One is the best phone for you, it is a great phone. It has a lovely display with good viewing angles, a more suitable processor for the resolution, the front facing speakers are really good as well. However if you do a lot of physical activity e.g swimming, hiking then the Xperia Z is a good choice due it being Dust and Water proof.