My Case had on the bottom of the "clip" exactly where the 4cm long recess that holds the headphone jack free, 2 small ridges. These have me then smooth on the upper edge of the Xoom, which is indeed made of plastic, also "reingerubbelt" 2 ridges.
When your finger over it goes to the bottom of the clip can be the notice. With a nail file can the then also come to grips with.
As the main criterion I set the protection of the Xoom in the foreground. And does the Case hervoragend in my view. One can see the foam padding also good in the picture, exactly where the bottom of the Xoom should hook when you set it up. These pads protect the screen really well.