Note: This is obviously quite delayed, but we're approaching the six month mark of the 5s/refresh cycle, so enjoy!
So, this is a little late. I wasn't originally planning on purchasing the 5s, as I purchased the 5 when it came out last year and saw no real purpose in upgrading (and I never usually do) to the 's' edition.
Then, AT&T happened. AT&T doesn't really do unlocked anything when it comes to their contract, so I needed to purchase a phone for my stint here in London, so off I went to pick up the 5s. I got the space grey version, and it is beautiful.
It's the same coloring as Apple has on their iPads - and it looks great. Not quite grey, not quite black. I will point out that it feels a lot sharper on the edges than my 5 did; it can be somewhat uncomfortable to hold at times.
For most people reading this, you probably already know the general differences (faster & lighter - effectively improving upon the 5's specs incrementally). There are two large differences that I would like to point out.
First, the camera. It's much improved from the 5 and the sensor technology that Apple uses blows away all most all competition (other than the Lumia 1020 and, maybe the Z1).
Here's a collection of shots I've taken with it. They are generally untouched other than some cropping or straightening.
It's definitely the best camera phone on the market (in terms of total package); I especially love using it with VSCOCam - a great photo editing application. The camera is not bad in low light situation either - it's no DSLR, but it can handle most situations that you throw at it with some grace.
As I walk around, I love having it with me so that I can snap a photo here and there of London that I don't have my GX1 for.
Overall, it's much improved from the 5 and one of (if not the) best camera-phone on the market.
The other feature is Touch ID. If you don't know what Touch ID is, it's Apple's fingerprint reader technology that they have installed in the home button on the 5s. It works great. You set it up by giving it at least one read of your finger (up to 5 different fingers can be installed at one time).
Once you set it up, if you want to unlock your phone, you just hold your finger against it...and voila! An unlocked iPhone.
It has another key feature to it, though. It removes the need of typing in your password when you're purchasing or downloading apps from the App Store, which is incredibly handy (hah!) if you're like me and have an obnoxious password to type in.
Some users have reported issues with Touch ID. It generally works like a charm for me providing you firmly press your finger into the center of the button - it works from any direction, though! Lightly pressing doesn't do it, and if your fingers are greasy or anything like that, it'll have a tough time catching it.
There is also the elephant in the room that needs addressing - iOS 7. It's different. There is no way around it. I can say that it has grown on me, but it is still quirky and buggy and relaunches every so often. It's half-baked, and 'unapologetically' not Apple-like.
That being said, there are features in it that I love and I've started to come on board with the design (other than the icons not being great), but also with how applications' designs have radically shifted and are beautiful (looking at you Evernote, Facebook Paper, and OpenTable). Every time I see an iOS 6 device, I just think - "wow, I used that?!". 7 is undoubtedly an improvement, but it is still not finished - hopefully 7.1 will help, but only time will tell.
Overall, I think the key to this phone, as with all previous "s" iterations, is that if you have the previous generation - there isn't much point in upgrading. I wouldn't have if I didn't need an unlocked phone. It's a huge leap over the 4S and it's the best iPhone on the market right now, so if you're looking for that - then definitely get it.
If you're just looking to jump from the previous model or another recent flagship, then I would probably advise you to hold off - at least until the 6 comes out.