Well-made shell to hardware switching between 2 Sim Card for iPhone 4 / 4S

I for two months use the Thumbs Up Dual SIM Case for Apple iPhone 4 / 4s now in continuous operation with my iPhone 4S. I can confirm that there is 7.0 Beta1 works with the operating system versions iOS 6.1.2, 6.1.3 and the iOS. I go about it on the assumption that it will always work, as it is in the changeover to a mechanical switch and not to a change in software.
I had tried as an alternative, a dual SIM solution of Pearl, in which a conductive path from the Simkartenslot comes out. This functioned poorly (there was also a restart of the device necessary beyond this solution works with iOS 7 Beta 1 NOT!).

The build quality is excellent. I would it 5 stars if I did not, the system would have to start again, with each new change. This is, unfortunately, every time necessary, because at a changeover during operation the message No SIM card is installed and will disappear after a restart.
However, I believe that the restart issue for manageable!
Therefore, I forgive 4 of 5 stars.