I had been using 5s as an optional phone with the other phone the speed ot gives is remarkeble comparing to any other iphone devices and mostly its very handy and compatible the big games and apps runs very fluently dont even glitch and I have been using about 5 years and not even one software problem or any harware problem I really love the phone sound quality is abviously good but the resolution of the screen not upto the mark good and sleek design and very user frendly