[Verizon HTC One (M7)] rickrobin:
(EDIT) Since posting the below, including edits, I have come to the conclusion that my phone is indeed defective, and am having it replaced. I'll report back.

I love the phone, but there are three major problems that prevent me from recommending it, although I don't know what else to get.

1. The camera. It has problems with focus, and the interaction between focus and exposure settings. It's hard to get a sharp picture out of it at medium to long range, making it all but useless for landscape/distance shots. The default settings let in too much light outside in daylight, resulting in hazy shots; and the only way to get a blue sky or anything close to enough sharpness to even zoom in just a little is to over-darken the shot by notching down the exposure and contrast controls. Indoors, there's flaring of brighter areas, and oversensitivity to the purple spectrum, as well as near impossibility of getting sharp shots at any distance. The auto exposure control changes the exposure so jerkily it's devilish to control. The wide angle and aspects of the big pixels show a lot of promise (and I'll bet the iPhone 5s with its 8 "ultra pixels" will provide proof of concept), but the way it is, the camera sucks. HTC says they're aware of this and working on an update. Uh huh. How long has this phone been out now internationally?

2. The speakers. A major selling point of the phone, and rightly so, as they really do sound great - especially with Beats on, or you can get more volume with it off, if volume is a priority. But the speakers are out of balance, with the bottom (right) one louder than the left, and there's some phase weirdness. For those of us who notice these things - this phone's natural constituency - it's really annoying. HTC says they "haven't heard much about this", but are looking into it. Meanwhile, I went into a corporate Verizon store and every employee in there with any experience of the phone said, "Oh yeah, everybody knows about that," and proceeded to give me the most imbecilic, trumped up explanations you could ever imagine. The kicker was, "They have to make the top speaker softer because they use it as an earpiece for the phone function."

3. BLUETOOTH. Unfreakingbelievable. If it hasn't been connected since the phone was last turned off, it will connect to your car radio automatically, as long as Bluetooth on the phone is turned on BEFORE the car. (EDIT - Turns out this isn't always the case, and may depend on the particular car radio.) But once the connection is broken, it will not re-connect automatically. When you try to connect manually, it may or may not connect properly, or may need repeated tries, or connect media but not phone function, or it may show it has done both but actually hasn't. But regardless, although the phone's music player will play, internet radio type apps will not play over Bluetooth - and the call quality will be greatly degraded. The only fix is to turn the phone completely off and on again - with Fast Boot OFF; a soft restart will NOT fix it - whereupon everything works fine. (EDIT - The foregoing fix also does not always work. With my car (2012 Subaru Impreza Ltd.), once the connection is successfully made, Bluetooth can be turned off and on again on the phone, and it will connect without a problem. It is when the car has been turned off that reconnection becomes a problem. My iPhone 4 worked flawlessly with this car.)

I really don't think my particular phone is faulty, in all these ways, especially since it doesn't have any of the other problems people have been reporting, and works perfectly otherwise. But please, somebody, convince me that it is, and I'll go get another one! Any case, there's loads of people having these problems.

(EDIT - further investigation with a couple of actually honest and knowledgable Verizon people has reinforced my conclusions, including the "loads of people having these problems" part, objected to by the commenter below. The camera is decidedly sub-par, the speakers are not in balance, and the Bluetooth, apparently typically of HTC, is badly done. These sources also reinforce those on this board who indicate that rooting can solve or improve these issues.)