The number of times I dropped my iPad and no problems, dented auliminium case, but glass intact...
Dropped iPad2 around 1m on to wooden floor. Case not dented but glass is smashed.
Basically I was folding the cover over the top, as you do, holding iPad with one hand and moving cover with the other. The cover detached (magnets) and as this was unexpected I droped the iPad on the floor. Crack.