The first real technical review of the HTC One is in [anand] - and it appears the camera is as good as promised.
For still photos the HTC One is better than anything out there including the Nokia 920, and much better than the SG3 or Iphone5.
And for video it is on a par with the 920 and better than anything else.
In low light situations the review says there is no other other phone that comes close at all.
So it would appear that Ultrapixels may have something going for them and not be the usual ballc**p we get from manufactures.