Just wondering, I have a 4S and waiting for my 5S. I'm interested to see if it's a big difference between the 4S and the 5S. There wasn't much info out there except for comparisons with the 5.
Most defiantly there is a difference! I am sure you will be pleased, as I certainly am! I went from the 4S which I bought back in Nov 2011. I just got my 5S on Sept 25th which I ordered online from Apple.com the second they started to take orders.
In no particular order...
Cellular Data Speeds: This of course depends on where you live, but my LTE speeds here in Columbus OH are pretty fantastic. In areas where I wouldn't even get 1Mbps with my 4S I am getting 10-20Mbps. My top speed so far is 32Mbps down and 12Mbps up (that is faster than my 30Mbps Down and 5Mpbs home cable modem service).
Still Camera: The camera quality is much improved (and that is saying a lot since the 4S had a really good camera in it). The 10 FPS burst mode is pretty awesome to have as well. It is crazy how fast it takes shots when you hold the shutter down. I love how you can select the best shots and quickly delete the rest. The two tone flash is nice, I don't typically like to use flash since the results tend to suck, but so far when I have used it the results are nice. Plus have a dual LED flash makes for a better flashlight when you need to use it (and is quicker to access now with Control Center).
Video Camera: The Slo-Mo feature is pretty cool and I have been having a lot of fun with it.
Touch ID (fingerprint reader): This is very nice to have and has been working quite well for me. Very nice not to have to type in my access code, or my Apple ID when buying items from the App Store or iTunes store. Apple did a great job in making this easy to set up and it has been very accurate for me in reading my finger print on the first try.
Larger Screen: Not a huge upgrade from the 4S but having a little more vertical real estate on the screen is nice for reading, gaming and viewing videos etc...
Phone audio quality: Not sure if this is because of the LTE, but the audio quality on calls is noticeably better.
Overall Speed: The overall speed of using the device and the smoothness you experience when scrolling through lists, opening up apps etc... is faster.
3G Gaming speed: Download the free 3DMark benchmark and run it on your 4S and when you get your 5s, run it on that. It is amazing how much faster it is.
Lightning Connector: Although moving from the 30-pin to the Lightning was a pain and cost me money in buying new cables adapters etc... The connecter is much nicer to use since you don't have to worry about the orientation of the connector when you insert it into the phone plus it is a lot smaller.
Then add the new features that iOS 7 brings like the control center, better multitasking etc... and I feel it was quite the upgrade. Even Siri works a lot better and is actually useful now.
A benefit in skipping the 5 is that a lot of apps now support the 5/5s/5c screen resolutions.
The only negatives which I hope are fixed with software updates, is that my 5s has crashed and rebooted about 3 or 4 times (which other have experienced). That is something I rarely if ever experienced on my 4S and previous iPhones (I owned the 3G, 3GS, 4 and 4S).
So I am pretty pleased with the upgrade and will be even more pleased once more bugs get fixed and apps get updated for iOS 7 (which a lot of the ones I use have been).