Each service promises good quality
Outside, after repair, all gadgets look the same. But inside there are a lot of screws and small parts, which are not all put neatly and in their places. A couple of months you can refuse the button Touch ID, the screen will be unfastened, the screws will twist and will rattle.
If the iPhone was protected from water and dust - service could not install a new gasket and the iPhone will die after the first rain, as in the photo.