In another post I had "confirmed" that the Snap Shield 2 fits the iPad 3, so I will chime in here with my unofficial FAQ(sorry, I write tech docs for none techs at work).
Does it fit?
Yes.
If so, why are others saying it doesn't?
Because it fits according to how the Snap Shield is suppose to fit into the iPads.
How is it suppose to fit?
1) The only edge that it fully wraps around and protects the lip of the iPad is the right-hand edge. This is the edge to your write holding the iPad in portrait w/ the camera at the top.
2) Both the top and the bottom edges of the case does not fully wrap around. The case only protects up to where the seam of the aluminum back meets the edge where the screen begins
3) The left-hand edge where the smart cover hinge sits will have 2 small tabs about 3/4 cm long on the top and bottom. They do wrap around a little.
4) How about the corners? All 4 corners have the case coming up a little bit and wrapping a little bit. They just barely sit and above the corner edges to protect, but aren't as tall in their wrapping as the right-hand edge.
So how do you know that the iPad 2 and iPad 3 fits the same?
Because I own both the iPad 2 and 3 right now. Due to this topic coming up, I have been putting this case on and off between each of them to compare.
Still, how come the OP had an issue? Surely they don't fit 100%?
Honestly, there is a slight difference in the fit between the 2.
1) IMO, the left hand side corner protection does not wrap as high on the 3 as on the 2. It might be a .20 mm lower. But, it still protects the corners just as well.
2) When I hold the iPad 3 w/ the case with both hands, the very center of the back of the case does not feel as flush against the iPad itself. When it is in the iPad 2, it feels tight. But in the iPad 3, it feels just ever so slightly loose(but not to the extent it feels bad or loose to come out. Think of it as your favorite fitted suit not fitting so well once you've gained a pound or two and your gut kind of pushes against the waistline(bear w/ the analogy, I write docs at work for non techs).
Conclusion
So there you have it. If you are super particular and care about those things I mentioned at the end, then hold off and get the one for the iPad 3. If you want to save a few bucks and it won't bother you(or you had one from the iPad 2), then get the one for the iPad 2.
Hope this clears things up