The HTC One has a higher ppi, but it isn't any sharper to the naked eye. Maybe under a microscope or highly magnified lens, but to the eye pixels are completely invisible on both. Hence why I left that out, and just pointed out that the S4 has a bigger screen.
Secondly, the S4
is more accurate in colours. It's actually the second closest phone to 6500k out there. Set to movie mode that is. The One is actually post 7000k, more towards the cool side.
The only fair thing I missed out was the image stabiliser, simply because I forgot. Also, less lag on the main screen is up in the air, please read my posts above. Seems like carrier bloatware is a big reason for some of that rare stutter on certain S4's, and also explains why many owners on these boards have never experienced any, but as mentioned, it can easily be remedied. Also, on actual tasks (web browsing, games, benchmarks, intensive apps etc) the S4 is faster, sometimes by a noticeable margin (especially in web browsing on certain sites like Verge). That I'd imagine is large in part to the faster processor and gpu.
Only reviews that state otherwise are likely those that did not look to tinker with the display options. There are several sites that use calibration software that have posted their opinions.
Here's a couple.
http://blog.gsmarena.com/samsung-ga...firms-amoleds-can-finally-do-accurate-colors/
http://www.displaymate.com/Galaxy_S4_ShootOut_1.htm