I have 3 phones - the Nexus 4, iPhone 5 and HTC One. Each has its pros and cons. I like each for different reasons. I don't like Samsung for a myriad of reasons I won't get into here because I don't want to start some flame war. Suffice it to say, their phones don't meet my preferences and needs.
That being said, I'm an iOS guy. That is my preferred mobile OS and I've had every iPhone since the 3G and every iPad. However, I truly do feel like the HTC One is the first Android phone, that if told I had to only keep ONE of my phones, I would choose over my iPhone 5.
Here's why:
-The HTC One meets (and even exceeds) the iPhone 5 in design and build IMO. They are the two most beautiful smartphones out there, but I think HTC knocked it out of the park Steroid Barry Bonds style with the One's fit and finish.
-The HTC One's display is absolutely phenomenal. I'm partial to IPS LCDs because I like the color accuracy and brightness. The One's display is a bit sharper than the iP5's due to the higher PPI, though it really isn't terribly noticeable and I wouldn't be able to tell if I wasn't staring at them side-by-side.
I go back and forth about the larger display. It's really nice, but there's something about the iPhone 5 form factor (display size) that feels more comfortable. To me, its a wash as there are some days I love looking at the big display on the One, and others where I just prefer my iP5.
-Sense 5 is elegant and minimalist. It doesn't get in the way and the software features it adds to Android are very useful IMO. Blinkfeed is wonderful, Zoe is neat and I love the weather widget. Sure its a bit more "locked down" - especially being on 4.1.2 (no lockscreen widgets without an app), but I find it to be the most similar in terms of design language and overall utility to iOS that you'll find in an Android. My Nexus is great, but there's just too much tinkering to do on vanilla Android to make it not feel "empty" or unfinished. I never get that feeling with my One.
-Those Boomsound speakers are incredible. I'm currently in the process of refurbishing my old iPod classic and don't quite have the money to buy the SSD I want to put in it. As such, I don't really have any "boombox" that I can listen music to in my man cave (yes, I have an amazing wife). The One's speakers are THAT good, that I really don't mind listening to music over the speakers of my phone. Would I prefer the classic plugged into my old dock stereo? Ya, but I was blown away by how good those speakers are.
-No hitches or "lag" on the One. I don't mean long periods of inactivity or anything. I experienced the relatively consistent hiccup here and there on my N4 and I've heard similar things about he GS4. I expect ZERO stuttering in a device with such a powerful processor - especially since I don't have any of that on my iP5 for various reasons (I know all about how Apple attains this level of fluidity). The One is the smoothest Android I've used - mainly due to the stripping down of Sense. I like the whole "add a few useful features and then get out of the way" approach HTC takes with Sense. (I also get to utilize more of the internal memory that way too without having the skin take up too much).
All-in-all, it would be a tough decision for me. I'm so used to the iP5 and iOS, things are second nature. I'm still relatively new to Android (the N4 was my first Android phone and I got it in February - had an N7 that I got last August, but sold it shortly thereafter). It think if I were FORCED to choose my ranking would go like this:
HTC One > iPhone 5 > Nexus 4 > Whatever Samsung puts out.
Now that's last year's iPhone and last year's iOS. Given the rumors about iOS 7 and an update to an iPhone 5S and that ranking could change given the top two are SO close.
But I can tell you this - to reiterate, I'm an iOS/Apple stalwart - if there's an Android phone that can dethrone the iPhone 5 in my eyes, its worth checking out IMO.
(to be honest, you'll find most Apple users/"fanboys" would pick HTC as their Android given HTC's willingness to play ball with Apple and the shared design mindsets - both similar in what they try to do, albeit with different base platforms).
*NOTE: This is all MY opinion and in no way reflects what I feel someone else SHOULD do or how someone else SHOULD think. Just my two cents