First, let’s address the elephant in the room, no one in todays date will buy a phone that was launched in 2013 and is currently four generations behind. The only reason someone would want to buy a 5S today is because it has the apple logo on its back. All this being said Apple’s Iphone 5S is still a great looking phone, if you are a minimalist user and like to perform all your mobile tasks by using just one hand, then the 5s is your phone. The screen and the build quality of the phone even after all this time outperforms many of the medium and lower end contemporary phones. The A7 chipset performers great but be wary the new IOS 11 puts a lot of load on it and turns it a bit sluggish, I would advice you to hold on to the out of the box IOS and wait & hope that Apple fixes the bugs on the 11 within a few months. The cameras( both front and back) can be graded average by todays standards and the speakers are brilliant for a candle night dinner with your sweetheart but is abissimal for a houseparty with your boys. But the best part about the 5S is that it still has a headphone jack, cherish it before its gone forever.
Finally, I would like to suggest that if you are Iphone curious and want to see if it’s for you than going straight for an Iphone 7 or 8 or prebooking the much coveted X would be a mistake. Get your hands on a 5S, play around with it, get a feel for it and if you decide you want a faster and better version of this baby then go for the high end models.