My only real negatives with the HTC One is call clarity and rear camera.
My Nexus One which was first released in Jan 2010 has better call quality and camera than the HTC One! I live on the 30th floor of a high rise condo. I generally cant get good reception in my room and the HTC One is no exception. I use the 4G toggle app on GSM-only setting. It kept the bars at steadier and full, but the reception from the other end still feels shoddy. The other caller can hear me but I cant always hear them. Also the speakerphone is pretty mediocre too.
And the camera is fairly disappointing. I was shocked to see a 3-yr older model beat it in nightshots. I took pics of an arena while waiting for a train at night. HTC One's pic felt like the contrast and brightness went too high. Exaggerated. I'm just not into these back illuminated sensors just like S-AMOLED that produce unrealistic colors. My iPhone 4 was the same way. Came out with a yellowish tint and the HDR mode made us look like we had a tan with indoor shots at night. While my OLD Nexus handled white balance better.
With all that said - HTC One does everything else better. Faster, smoother, classier design, bigger and better screen, better for audio externally and internally, better at playing games, videos, picture viewing, web browsing, excellent video recording, respectable front-facing camera, and better batt life compared to my Nexus One. BlinkFeed is much slicker than Flipboard widgets with that Windows Phone-inspired tile effect. Only thing I miss from my iPhone 4 was batt life esp on standby. I got 9-10 hr screen time batt life and weeks on standby. I can get abt 6-7 hr screen time if I'm just texting and not browsing or playing games on the One while with the old Nexus I get abt 5 hrs tops ON airplane mode doing abt anything. And iPhone 4 vs HTC One's cameras are about push since both give me yellowish shots. I'd favor One since it can be a tad sharper, faster, and video recording and front facing cam is superior.
Even with those two flaws like reception and disappointing Ultrapixel camera for still shots, HTC One is still the best phone I ever had. People need to realize no phone is ever perfect in all areas. I suggest to anyone to have two phones. One smaller and one bigger to see the benefits from both sizes. Complimentary to each other. And I suggest getting the HTC One now if you like Beats Audio. Now that Beats bought back the rest of its shares from HTC, the successor to the HTC One may no longer have it.