It is odd to me that there are so many case manufacturers who are selling the same unit for all three models, even though the dimensions shifted between 2 and 3. I haven't been able to get my 4 to fit into a Ridge case that is supposed to fit all three. I guess it's possible that I have a defective iPad, but it seems more likely that it's a case issue. Of the cases that I'm interested in, I've seen reviews on all of them that mention the 4 not fitting properly, but then others that say it does. What are your experiences?