I work with mobiles, I'm not 100% how the American carries work (But from what I've heard, I feel sorry for you guys, it seems quite shitty) but I can give a breakdown of the general pro's and cons of the more popular ones.
I mainly deal with software issues at work, but sometimes I gotta sort some hardware issues, I can fix phones but I'm not meant to as I'm not an engineer, anyway...
HTC One
Pros
- Excellent build quality and size.
- Good multitask feature
- Speakers are fucking good
- Looks awesome
- UI is simple and clean
- Really awesome if you 420r00t it and get the HTC button to work
- 32GB minimum of internal memory
- Camera is awesome
Cons
- Sense UI looks outdated compared to stock Andriod (Slight contradiction, but if you use one and try and Nexus 4 you will see what I mean)
- Software features have stupid names, blinkfeed, zoe, boomsound (Not really an issue but a gripe of mine :D)
- Internal memory, it's good that you get a lot built in but SD cards are a must for some people.
- Some of the default SMS, Music players are really bad, this is on opinion but the HTC music player is one of the worse I've used.
- Only 4.1
Can't think of anything more for now, it's a really good phone, I would get one but I really like my phone to not have much manufacturer software on it, mainly because I'm not a fan of the Sense UI. If you can overlook that then I'd say go for it. It's one of the best out there.
Galaxy S4
Pros
- Memory 16, 32, 64 available and SD expandable as well.
- Awesome display
- Removable battery, now this is really good as the amount of issues that people have with their phones (battery life, freezing, signal etc. etc.) can be solved by just pulling that bitch out and slamming it back in.
- Pretty sleek design
- Has the same features from the S3 which were awesome.
- Has 4.2
Cons
- There's a load of features that are pointless, Smart Pause, S Health, S Voice, fucking wizard touch shit, the features added to the S3 were awesome, the ones added to the S4 were things that nobody ever wanted.
- Bloatware, because of the large amount of features, the software takes up around 7 GB of the 16 available, include your carriers bloatware you could be left with around 6 GB of internal memory to use, take note, some apps can't be moved to the SD card.
- Build quality is pretty poor it's quite a fragile thing and the screen can crack easily, I've already seen plenty that have charging ports already break.
- UI is just not my taste, the whole nature shit isn't what I want in a phone (again personal preference)
- The settings menu is really really bad, I have no idea why the tried to organize it but they have tried and they have failed.
I'd rate this lower that the GS3 imo, the screen is awesome and it looks nice, but as soon as you start using it to me that's when it starts to get a bit shit. Again, having a CM mod is the only way I'd use this phone, and if you really like Android this phone really does a good job on making it not look like Android at all.
In all honesty, I would say get a Galaxy S3 or a Note 2 over an S4, you have less features but you retain the good ones, there's less intrusive software on them and they are still awesome phones.
Xperia Z (I have this)
Pros
- Good build quality, very strong, I've dropped it loads of times on purpose to show everyone and there's not a scratch on it, and it's MOTHER FUCKING WATER PROOF WHICH MEANS TAKING PHONE CALLS IN THE SHOWER.
- It's just a re skinned version of Android so it's close to stock which is what I like about it.
- Quite a decent portion of the manufacturer software can be removed, the rest are things like diagnostics, battery saving (stamina mode), backup etc.
- Looks awesome, the screen is very good and the design is pretty sweet.
- SD card support (only up to 32GB) with 16gb internal
- Sony have awesome developer support if you like fucking with your phone,
OH SHIT I RAN OUT OF SPACE