Iphone 5s is great device which powered by apple a7 chip whose performance is bit similar to the a8 and a9 found in iphone 6 and 6s this device comes with touchid which is great, it also supports slow motion videos and has a 720p display which is ips and has got great 8mp back and 1.2mp camera at the front the device has 1gb of ram which is quite good as the device is very smooth as it is well optimised with hardware and software and you will never notice a single lag or hang.
But the device will dissappoint you when it comes to battery it has got small battery which may give you 3-4hrs of on scrrentime and expandable storage may be issue for some user but if you are a apple fanboy and wants great optimisation and no lag and hang great camera with slow motion video go for it will never let you done and buy a small powerbank with fast charging so you may charge the device when you feel short of the batttery