I have been using iPhone 5S from past 5 months. It has great features looking awesome, UI is too smooth, Camera is superb, Speaker is loud enough. Processor and RAM: The 5S has only 1GB RAM and a Dual Core processor which seemingly pales in comparison to what other flagship phone have to offer. Fastest phone ever tested till date.
Special Feature: Fingerprint Scan and unlock your phone. People may argue over the pros and cons of such a feature but I would personally prefer such a feature which I will certainly make use of; instead of an almost useless fancy feature which I rarely use.
But very poor battery back up. There’s no phone like an iPhone