Been using the One for a few days now and love it. Came from a Note 2 and although I miss the screen size, the One is just a beautiful piece. I do have some critiques though....
screen size a bit small for my personal taste but the clarity makes up for it. I would have prefered a full 5" though.
Boom sound sounds great! Speakers could be a bit louder though but FINALLY front facing speakers! I still cup my hand when holding this phone though out of sheer habit.
Software......ugggg the software. HTC REALLY needs to invest in some better testers. Although not terrible, there are some bonehead things going on in Sense 5. Changing out shortcuts on the bottom launcher comes to mind. I almost returned this phone when I thought I couldnt change stuff around. The lack of a launcher on the drop down screen is another. The note just seemed to have endless settings compared to this thing. Oh and the facebook mess in the gallery! My wife has already said she is not getting this phone and instead getting a S4 due to that. Shes a big facebooker but refuses to have to sift through her friends pictures everytime she looks in HER gallery. Just dumb all around. Also any live wallpaper I put on here is just not fluid. I have read that it was a issue with previous HTC's and Im bummed to see it hasnt been fixed yet. Its not all bad though, I do really like the camera features. I really like Zoe and how the phone makes the little videos. That was a homerun in my opinion.
I almost returned this phone more than once and went back to my Note 2 but the hardware kept pulling me back. Its just a stunning looking phone and I keep telling myself all the flaws I find are fixable with software updates.