Had a brief play with the new HTC one today, wow!
It's a pleasure to hold, and feels perfectly balanced. The Lg flex is still my work horse (just had kitkat update). But for a smaller phone there's nothing around that feels as good as the new HTC. I like the larger screen size and the louder volume which still has the best audio quality of any phone. The sd slot is a nice addition, though I've gone off sd cards for security and lag issues (on certain phones). A higher resolution camera would have been nice, but for my usages, the HTC one camera is more than good enough and better than some for certain situations. I can't really justify buying it, but it's a world of difference to the s4 I used to have, and even to the g2 (though I like those back buttons). If I was going to get a new phone I can't see any other phone around or due soon that comes close (though will be interesting to see the rumoured iPhone 6, 4.7" and 5.5").
But if I had only one phone for work and personal usage, for the extra productivity that the 6" screen gives me, whilst still being able to use one handed and feel comfortable, the Lg flex is still my first choice (though picking up the HTC one a few more times I'd become less inclined to let go of it!).