[Nexus 5 Q&A, Help & Troubleshooting] skyo12:
Just switched 2 weeks ago due to QC issues on the HTC One (I was on my 4th unit). I really wanted to love the One but I just didn't want to play the refurb game anymore.. with that said here are some notes based on my experiences so far. I currently have the Black/White 32GB Nexus 5 which I have used for about 2 and a half weeks and had the silver HTC One 32GB for about 4 months.

Display: Both have fantastic displays. Nexus 5 does seem to have a bit more washed out colors but it's negligible in my opinion and it produces a more realistic color representation when both screens are on default calibration. I would give the slight nod to HTC in terms of quality, but a push overall since Nexus 5 has a bigger screen.

Radios/Call quality: I'm on T-Mobile currently and the signal strength for data and voice calls were pretty much even. I would actually give the call quality a slight nod to the Nexus 5 in terms of clarity on both ends. Both phones gave me no problems in terms of radio performance.

Camera: I read reviews where HTC One camera was getting critical acclaim.. I have no idea why. One camera had some great software features and the low light performance was OK, but overall I would take the Nexus 5 camera in a heartbeat. Nexus 5 camera provides more details obviously due to the higher pixel count, better color contrast and it just takes better pictures consistently in good lighting settings. Things to keep in mind though is that HDR mode takes great pics, but shutter lag is noticeable in that mode and camera recording is not possible in HDR so any low light enviornment produces basically pitch black video.

Performance: HTC is no slouch but the performance is definitely better on the Nexus 5. I'm not a gamer so I can't comment on that front, but apps open faster, browsing seems snappier, and it just seems more fluid.

Software: Nexus 5, no contest. Sense 5 is ok, but it had a lot of annoying features (app drawer in particular) that just annoyed me.

Hardware/Build Quality: Everyone knows the specs in and out by this point, so I won't go into that. HTC definitely feels more premium due to the aluminum chassis and it's a little more comfortable to hold due to the curved back. The HTC front speakers are also phenomenal... Nexus 5 does not compare. Now, all I said was that the HTC One FEELS more premium, I actually like the design of the Nexus 5 better due to the minimalist design and the black/white contrast along with a very light weight feel.

Battery Life: Honestly, the speakers and build quality is an added bonus but battery life is the most important feature for me on a phone. I have headphones on at all times, and build quality only gets you so far (and as I mentioned, premium feel but I'm on my FOURTH HTC One) so the extra added feature of the One does not give me an added benefit for the most part over the Nexus 5. For my usage which consists of 4 email account on 15 minute sync, streaming music for an hour over bluetooth, 30 - 60 minutes of calls, watching some youtube clips, reading the news or books, checking fantasy sports teams and browsing the web, I can get 20 -24 hours of usage with an average of 4 hours of screen time on the Nexus 5. HTC One was about the same but for some reason, it was less consistent and on average get less screen on time.

In conclusion, assuming I had absolutely no issues with HTC One during my 4 month of ownership, I probably would not have changed to the Nexus 5 since it's not a significant upgrade. Now, if I was shopping for phones currently and had the choice of purchasing either device, I would pick the Nexus 5 in a heartbeat. For me it comes down to the fact that the Nexus 5's value for the price is just ridiculous along with the fact that it's SIM unlocked for THREE of the major carriers in the US. And of course, the hackability and the developer support for the Nexus products are unmatched :laugh:

EDIT: I should also add that both phones were rooted but pretty much stock for everything else.