the
4s had "fake" 4G the 5 and 5S are true LTE.
I went from the 4S to the 5S and was was quite surprised at the speed jump. not just network speeds but everything is just faster.
the size change was a bit annoying at first ( I've had every iPhone since the original with the exception of the 5) but I got used to it
My personally belief is that your already used to the apple eco system.. have other hardware in the same eco system you'll be happier staying there.
For me as I have 4 macs sitting within sight of me right now plus iPhone 5S, iPad Air, and AppleTV Gen3. going to Android would probably annoy me more for loss of interoperability then any advantages I might gain.
The fingerprint unlock is cool and useful.
the LTE speeds on AT&T are great. here is a test from a few mins ago
