Okay, I've found more information about the HTC One camera problem:
First, after taking dozens of photos with the camera, I discovered that the problem seems to occur *only* when a very bright area is visible within the camera frame. Anything with a bright spot, anywhere from the reflection of a floodlight off of a shiny brass statue (or a plain white wall) to a photo inside of a bus (sunny outside) seemed to throw the camera for a loop. I took photos inside, outside and everywhere I could think of before I noticed the common theme with bright lights (or perhaps high contrast) causing problems.
Second, I talked with HTC for nearly an hour about the problem. They had me do numerous resets, restarts, and changes. Finally, after the HTC tech consulted with the Nth person for more information, he discovered that the problem has been confirmed by the tier-2 support guys, but nobody had told this to the tier-1 support guys. He promised that HTC was working on a patch for the issue via firmware. I was skeptical, but I gave him the benefit of the doubt.
I did notice, while talking to HTC, that in low-contrast situations, the camera auto-focused very well and very quickly. Add a bright spot, and suddenly the camera worked like a madman to focus. It was happening so fast that the image on the LCD appeared to be jumping up and down. Tapping on the screen to pick out a specific point would cause the image brightness to change, but the focus still kept jumping. Remove the light, and the camera locked on target immediately. I gave all of this information to HTC, so it's on record with them.
Then today, while browsing around for more details about the camera problem, I ran into this page at T-mobile:
Camera focus issues: HTC One (LTE)
The article is dated May 7, 2013. So I guess I'll just wait and see what happens.
The rest of the phone is great. Reception is as good or better than my dad's Galaxy, it's fast, and I have a ton of memory to burn (about 11 gigs of apps, video and music loaded, leaving about 2/3 of the memory free). If I can get my camera to focus properly, I'll be one happy camper!