Mine slipped out of my hand while I was walking. It went flying a good three feet into a wall, took some paint off the wall and landed on the floor. Screen is just fine. No nicks either, not even after I rubbed the paint off it. In total I've dropped it three times. Another user here fell on his and bent it. Screen survived just fine.Dont worry so much about scratching the back as dropping it even a short distance and smashing the screen which id what happened to mind EVEN in a well protected leather case. The screen is VERY THIN.
From our anecdotes it's invincible, from your anecdote it breaks if you as much as breathe on it. The reality is probably that the thinner glass doesn't make it any more fragile than a normal iPad or an iPhone. The screen on both of those can crack just from it sliding off the couch onto the floor. It's just a matter of luck.