My Mag Snaps for all of our iPad 2's held up remarkably well. Very sturdy, great protection.
As for the "third position," that's actually why there are two metal plates on the back of the case. The one closest to the edge is for holding the Smart Cover in the fully folded-back open position. The second is a little further towards center and is for holding the smart cover in that "third position." I've tried doing this with a non-Mag Snap and while its fine for viewing, it won't stay in that position if you try to type on it....the Smart Cover slips and the iPad falls flat.
That's what this third position is for...typing and using a stylus. It creates a rock-solid sturdy platform for that use. In fact, I think its the best stylus/note-taking/sketching position available. Its far better than the "triangle wedge" of just the Smart Cover as that lays the iPad out at such an angle that everyone can see what you are writing/drawing, plus it really lets the overhead lighting glare on the screen. I prefer to keep my notes and sketches to myself.
So yes...I do think its unique for all the other back cases out there.