After a week of research (the expensive original cases by Apple seem to have no good durability, many other products result in scratches on the iPhone ...) and the purchase of a not completely final cost envelope, I have decided for the Bumpercase of Spigen. The product comes packaged well, therefore, is protected by protective films on both sides of the transparent area and is well processed: the transparent back, which makes it possible to look at the great back of the iPhone seems to be quite scratch resistant. The Aussenbumper is tight enough and has interesting details like "supporting feet" on the back: so the transparent back has no contact with the pad. The buttons can be easily operated. Due to the quality plastic processing, the iPhone is not much thicker / bigger acts. Single - system conditional - drawback is that at the bottom is not a sufficient contact to a dock and adapter plugs. I've even a Lightning male / female adapter ordered from China, let's see if that works. But this Janke's get over to me in view of the extraordinary qualities of the other shell.
I hope that life is good because I'll JRC. soon a little nachposten.
About the low price of ten euros I did not say anything yet! But even for more money I give here a strong buy recommendation!