Made the switch to the One when it was released. Came from a beloved DNA and glad to have made the change.
Love the DNA, it is a remarkable phone; The One is simply the next step in the HTC evolution.
The aesthetics, build, storage, battery life and speakers alone are enough to make the change.
The One's screen is smaller but negligible, at the same time this gives you a pixel density of 468ppi vs. 441.
The One's Snapdragon 600 at 1700 MHz is "snappier" than the DNA Snapdragon S4 at 1500 MHz.
On the other hand I miss the inductive charging but had to return one DNA due to overheating while using this feature.
Overall the One is simply better, marginally perhaps; just like the next HTC release will be better than the One.
If you are in a position to make the switch I would encourage it but with the understanding that the DNA does pretty much everything the One does....and the Samsung S3 does more or less what the S4 does, the MotoX does what the Razr Maxx does.....and so on.
I make this point because most new releases barely trump what currently exist and that's probably the cycle that smart phones are on. Do any of us really utilize the full capabilities of what exists today, yesterday or better yet, tomorrow?
The smart phone manufacturers know that we are suckers for the next thing, regardless of how significant or insignificant the differences may be.
Look at Apple, they just released a cheap plastic version of their iPhone 5 and people lined up for it.....go figure.