I have the HTC Evo (4G LTE), precursor to the HTC One.
Good transceiver, gets signal and makes & holds calls in poor signal area. Good noise damping on microphone. Decent speaker. I can use the TuneIn Radio app to listen to streaming radio and the quality is not bad. Better, of course, when I switch on the Bluetooth portable speaker (a stubby tapered cylinder with a 35mm driver -- fills a room with sound).
Good WiFi reception. Good data rates. Actually, good data rates even on 3G.
Good camera. Not "outstandingly" good, but good nonetheless. Takes stills & video, takes stills
while taking video, has various modes including panorama. Good results in ambient light.
See here for examples, still life in ambient light, outdoor, outdoor pan shots. (Taken today, actually.)
Good app integration.
Good screen, good touch response. (Using screen as camera viewfinder in bright outdoor light kinda sux.)
I installed MobileGo backup, and the phone evidently supports peer-to-peer WiFi connect, so I don't have to use USB to connect to laptop when backing up my stuff. (Good app, BTW, saved my butt when the first phone developed a dead spot in the touch screen.)
Fits in my shirt pocket, which is where it rides.
Good -- actually
very good -- battery life. I can talk for three hours without a break. As long as the screen is off, you can do phone conversation, listen to streaming radio, and stuff like that and do the whole day. If, however, you wanna play video games on it (screen constantly on), you can drain the battery in four-ish hours of constant play.
I don't know about the HTC One, but my only beef with with the HTC Evo is that the battery is non-removable. Hasn't been a problem in a year of using, but I prefer to be able to have a spare. I contented myself with spending $60 on a "power source" type of charging brick. You plug that thing in, let it charge all the way, and then -- with the phone battery way down at, say, 15% -- you can plug the phone into it and continue to use the phone while it -- get this --
FULLY recharges the phone over a couple of hours. One could argue that the brick is every bit as good as a spare battery, maybe better, since it doesn't care what phone you're charging.
All in all, a good phone. If the HTC One improves on that, then I can recommend it.