Welcome Jason. Thanks for your service!
I have an EX-21. The 30 would be nice, in some circumstances, but first of all, it wouldn't fit in the designated "scroll saw corner" of my shop. Also, consider the ergonomics involved with spinning a large piece in the saw, especially when making cuts in the corners. If the piece is so big that a 30" capacity is required, you're probably trying to reach a lot of places that are going to be really tough to get to. Even if it does fit in the saw, it can be hard to see what you are cutting in the far corners. It can get pretty awkward sometimes, which is why a lot of folks use spiral blades for larger pieces. I certainly don't want to discourage you from getting the 30. If you have the budget and the space, go for it. It's a fine saw.