There’s is not much to say about the iPhone 5S’s performance here other than that it’s blisteringly fast and very reliable.
I’ve not experienced any issues with apps misbehaving other than the Google Maps hanging occasionally. It’s annoying but may be as much down to the app as to the phone.Apple’s iOS has its limitations, you can’t customise to anywhere near the levels of an Android phone, but the fact that it just keeps working well is a godsend to those too busy to learn every little foible of their phone.