Here is my review for iPhone 5s
Few Days Back My Father Bought an iPhone 6 GB for himself and i’m using iPhone 5s
He were using preinstalled calculator app on his iPhone 6 and whenever he opened calculator app the phone stuck on app
And he clicked home button it came back to home screen but again he opened calculator app the phone was showing a black screen
He tried the same thing 3-4 times even he did hard reset his phone but iPhone 6 was stucked on calculator app again
And he took my iPhone 5s and Snapchat , Whatsapp , Instagram , Facebook , Messenger app was running in background and still 5s was working so good