Those hair thin aluminum bumper cases wont do squat, the thick glassM m shields wont do squat. The device is just too long and think. Your best bet is to treat it like a full size tablet. Dont sit with it in your pocket, dont put it in your bag without being in a separate compartment. The poor thing is like 1/4" thick and made out of aluminum and glass. I still dont know why they choose this glass. I can take my droid incredible with gorilla glass and pound the screen on the corner of a desk over and over, no scratches. This sony phone just doesnt have any flex for the glass.
I just through an iLLumiShield on the front and back so i can throw it on the table and not worry about scratches.