That case is very similar to the Case Mate holster http://www.case-mate.com/s.nl/it.A/id.254/.f. It protects the iPhone well enough but the bevels around the screen can be quite intrusive making it really difficult to reach the Q and the P at the outermost edges of the keyboard.
I am considering the Vaja iVolution holster for precisely this reason. (www.vajacases.com).