I learned my lesson with the last couple of iPads I bought--I never trust 3rd party cases this early in a launch. They often either don't fit correctly at the corners, don't line up correctly with ports, speaker grills, etc., or don't fit snugly enough in general, which can cause more damage to the iPad than just not using a case at all.
This was an especially big problem with my 10.5" model. I bought two different back covers on Amazon from two different companies--neither of them fit correctly. Eventually decided to throw money at the problem and get a Tech21 back cover, which I used for quite a while, but it was SO EXPENSIVE.
This time around, I'm just thankful that there is an Apple manufactured solution that covers the front and back so I can have peace of mind when I lay the thing down somewhere and I know that it will fit right out of the box.