this is the reason I returned my first case lol, the top is slightly raised up where the top half meets the bottom half on the back of the case. after a week or so the case became loose and that spot in question started making a clicking noise. It seems like the top half is slightly bigger than the bottom half.
the replacement I received is exactly the same, so I'm pretty sure it will also become loose over time. I still think this case is sexy as hell and looks much sleeker than the silicone case (my other favorite), but for $30 I am kind of disappointed.
both cases had the "rubber" inside, so that improvement obviously didn't fix the fit of the case.