I am always worried about little hands walking around with the iPad. I envision 1 little slip and it is crashing to the floor. At the BYTE conference I had the opportunity to see some of the cases first hand. Do I know which one is best...... Not really. I guess it depends on what you are looking for and for who.
My thoughts are in a primary classroom or with a special needs child you need something sturdy, accidents do happen.
Here is a link comparing some of the different cases available.