I love specialty rulers, however I do try to make sure it actually does something I don't already have a ruler that will do it as easily. That is the main reason I did not buy the Folded Corner Clipper ruler - I didn't see where it would be an improvement over what I already have.
I am more likely to pick up a specialty ruler if I see it, if I have to order it, I'm going to think about it a lot more before doing so. Unless MSQC has it, then I'm more likely to toss it in the cart with my next order.