A little scared of the negative comments on this shell, I 've still ordered. I had indeed used the same for my Galaxy S2 and S3 my, I am told that it would go to the S4 and I'm not disappointed.
The shell protects the phone well, the rubber-like material avoids drag and allows different holes to let the free sensors.
In short, for the price, this is perfect for me, I see no fault.