[Galaxy S 4 General] bnathan:
I have seen SO many threads about the pro's and con's of both handsets and most are based on bias because people just want to justify their purchase one way or another or are comparing 5 minutes of use in a shop with their every day phone. I have now got both phones and here is my "opinion" of the pros and cons for both....

Screen:

The One's screen is stunning but feels small compared to the S4 and while I am one of those people who prefers the unnatural oversaturated colours offered by the S4 the sharpness seems way better on the one. Icons on the S4 have a slight fuzzy look to them compare to the One like a JPG being stretched. Could all be down to the screen size which as I said I much prefer the S4's larger screen.

Design:

This is a lot of preference but anyone who says the S4 is better looking than the One is on crack or like I said justifying their own purchase. The Samsung's plastic obviously has benefits like being able to change the back cover when it is scratched and removable to access the battery or SD card (which I don't care about the battery as I don't keep phones for longer than 12 months usually and as long as the phone has ample storage for me I am fine). Also the plastic on the S4 feels greasy and gets dirty with fingerprints very easily. One thing that a lot of people don't like that Samsung keeps doing but I love is the physical home button. The fact I can with one hand turn the phone on with the home button is WAY better than the two handed approach with the One which the power can only be turned on by the power button on the top left. On a funny note I left my old S3 on the S4 box in my office and someone walked in and picked it up and said "wow how amazing is the new S4 it looks so much better than the S3", might be a good thing because people obviously like the look but it shows that the 4 isn't that big of a difference from the 3.

Camera:

This has been done to death but believe me that both are great. If the HTC had a 8mp camera it would be the definitive Android phone but it doesn't. Both has a lot of tricks and features and both do a great job. The HTC does a better job with low light and with moving objects and the S4 has way more details.

Sound:

HTC wins this hands down. Not only with the built in speaks but with headphones too. Samsungs audio player also pales in comparison to HTC's which is as with everything on the HTC beautiful and consistent with the resat of the OS but also correctly downloads album art and lyrics to play in a Karaoke mode.

Software:

This one I am really in two minds about and my comparison is purely on stock.. The HTC's new Sense is pretty amazing. Its fast and has a consistency in its look that Samsung should take note of. I have owned a S2 and S3 and Touchwiz has barely changed. Why is the SMS app black but the mail app is white and the calendar app is a wooden brown? It seriously feels like Samsung has way too many programmers working on Android and gave them all one app or part of the interface to work on and didn't allow them to communicate to the other people to get a consistent look. Its ugly and isn't customisable in many situations. I have shown people the S4 and they marvel at how smooth it is but until you actually run it along side the One for a period its hard to describe how much smoother the One is. Never stutters never and little pauses or skipping of animations like the S4 does. On the other hand all the things the S4 can do are cool, if not gimmicky and useless. Samsung have better support from developers and as such things like my Fitbit sync wirelessly with the S4 but not my One, Grindr crashes constantly on the One and more. Support for the one is pretty amazing already and its still brand new. I also love the fact I can download a ROM and easily install it which you can not do easily on the HTC. I only every use stock but I will use the Stock UK or American or German or what ever version is the newest as here in Australia new ROM are usually released pretty slowly. It becomes an addiction every day looking if a new Android version or ROM has been released to install and try on your Samsung. 90% of the S4's new features I have turned off, they aren't guaranteed to work 100% of the time and can be more trouble than they are worth. Example Smart stay... this rarely happens but it does happen and did happen with my S3 too is that I will put the phone down on my desk at work and it will never turn the screen off, some how it thinks my office's ceiling is a face and stays on. The one feature I do love of the S4 is the one where you wave your hand over it and it lights up for a few seconds to show the clock and alerts then turns back off. Also something simple that the S4 does that the HTC doesn't which I didn't realise until I had both was when you get a message or alert the Samsung turns the screen on and displays it (admittedly in an ugly pastel coloured but for SMS's) but the HTC will never turn the screen on unless you press the power button. I will also mention that Samsung's Touchwiz also seems unpolished and incomplete, little things like the MP3 player on the lock screen not correctly fitting and cutting the bottom off just makes me think again that Samsung's developers didn't work together to produce a single OS but instead a mish mash of individual bits to make one up (maybe they rushed it out to steal some of HTC's thunder).

Hardware:

Obviously Samsung wins this hands down but once again with Touchwiz slowing down the S4 the One just feels faster. Benchmarks are great but you don't live your life in a benchmark how the phone functions in every day use is what counts. All the sensors and support that Samsung has is way better than HTC. Just simple things like putting a magnet in the phone so covers know when they are closed and turn the phone off. Simple yet awesome. The fact that Samsung continues to make a flagship phone with only 16gb and then used up over half of it with is ugly bloated OS is just beyond forgiveness. So many people say well use the SD card but always remember that you can not install apps to the SD card and a few big games and your phone can be full. HTC has a 32 and 64gb model readily available here in Australia and I guarantee that the 32 and 64gb models of the S4 NEVER get launched here just like they did with the S3. SO many promises broken, no size over 16gb and no wireless charger released even though they showed them off at the launch.

Battery:

Both easily got me through a days use. The HTC didn't last as long in standby and the S4 didn't last as long in use so they pretty much evened each other out. The fact the S4 supports wireless charging is a huge plus for me. People ***** about its useless and not as fast as a cable but they obviously don't get it. With wireless Qi charging you can still use the cable when your in a hurry and need a fast charge but the convenience of just sitting the phone on my desk charger at work and its charging is priceless. I work 9-5 so if it sits on the charger for 8 hours then its never going to go flat on me. I don't have to worry about one of the staff stealing my Micro USB cable (which happens all the time) or even looking for a cable its just amazingly convenient to sit it down and its charging. I have ordered one of those Chinese Wireless Qi inserts for the S4 and cant wit to use it. You cant add that to the One and the One is very slow charging. VERY SLOW.

Conclusion:

Both phones are the pinnacle of Android technology right now for mobile phones and both deserve to be hugely successful. In the end I stuck with the S4 as my every day phone simply because the support it has from app developers like fitbit like I mentioned before, optional wireless charging, the home button, the screen size and the fact I can flash ROMs when ever I feel like it. Every now and then I think I have made a mistake and should keep using the One, mainly when I look at how ugly Touchwiz is and when I get stutters in the OS which is unforgiveable for a phone with this kind of power. All the flaws in the S4 can be fixed with software and I one day hope Samsung wakes up and makes Touchwiz have the same beautiful look and constancy of Sense, till then I will download other apps to replace Samsung's and hope the speed issues are resolved in updates in the future which I can flash so easily when ever I want to.