How solid is the built-in stand on that incase book jacket? I've considered it as an alternative case but it looks like it could slip out of the notches for the various angles.
I have the apple case. It's not the most exciting of materials but I do like the design of the clip in back. People have mentioned it being prone to tipping over when it's sitting vertically but mine seems quite solid. I wouldn't leave it near the edge of a table or in a room with a strong breeze, though.
It's more comfortable sometimes to hold it clipped while reading for long periods. The wedge shape gives you more to hold on to. I found myself doing the same thing when I was using a kradle for my Sony Reader - picking the whole thing up and reading that way.
If I were to improve on it, I'd like one made of leather (which is simply not going to happen with Apple), or to have a magnetic closure. Magnets would likely interfere with the compass though - holding my Sony Reader with all its magnets up to the iPad certainly does.