[One (M7) General] BarryH_GEG:
You guys are confusing the objective with the subjective. Subjectively I've seen some absolutely fantastic pictures taken with the One including some posted in this thread. A 4MP camera is a 4MP camera and nothing is going to change that. A faster shutter and larger photosites can't compensate for half the detail compared to a 8MP camera and a third the detail of a 13MP camera. No one here would buy a high-end phone with a 4MP camera today; even entry-level phones and tablets have 5MP cameras. HTC could have made a UltraPixel camera with 8MP but tthe space it would require made it impractical. So to get larger photosites in a slim phone the trade-off was lower MP. Not to say that's a bad thing but it is a trade-off. The upside is outstanding low-light performance, great actions shots, and pictures that look fantastic social-size. The downside is lack of detail, average bright light performance, and pictures that don't look that fantastic when viewed on a pixel-to-pixel level. Most of you would have bought the One even if it had a standard 13MP camera because (for most people) the camera's just one feature to be considered. So debating whether it has limitations is kind of mute because it's certainly not going to change anything.

HTC's processing algorithims and post-processing have always been funky and that has nothing to do with 4MP or bigger photosites. Here's what Brian from Anandtech said and he's a big fan of the One's camera.

In location 7 (shown below) I see a lot of sharpening going on which affects the readability of the menu beyond just the loss of resolution from the camera being 4 MP. In outdoor broad daylight, the HTC One is admittedly at a bit of a disadvantage if you’re looking at things 1:1 on a high resolution display. On a 1080p display or shared on Twitter however, the images from the One are more than adequate.​

There’s still some visible noise reduction at work here which doesn’t make sense since this image was taken at ISO 101. In fact that’s my one big overriding thought about the HTC One by default, there’s a strange combination of noise reduction and sharpening going on at some times, and at first I thought this was overly aggressive JPEG compression, until I learned this is set at 95-percent quality. It is definitely noticeable in the homogenous color regions and textures which there are a lot of in the lights on test photo.

What sticks out at me is how much the subtleties of the HTC One match the HTC Butterfly, it’s obvious how much of the regional tastes of their camera tuners makes its way into the images. Both have a bit too much sharpening for my tastes, and virtually all the smartphones lose a lot of detail to noise reduction but still manage to have surprisingly noisy sky texture. I still can’t shake the impression that HTC has some JPEG artifacts which accentuate the noise in these relatively homogenous regions as well. Apple seems to reflect the kind of tuning I would find myself wanting the most – minimal noise reduction in-camera, encode the noise out, and don’t risk losing any detail. HTC seems to go for more aggressive noise reduction which occasionally leaves that oil painting look.​

This is from the beach scene above...

These are some other shots taken by owners...

And these are from a One X...