I love my Studio. I have bought Go dies, Studio dies, and Sizzix dies. I have most of the strip sizes in mostly the Go format, I have rectangles, and just used my 2" square Go die for a mystery quilt I am working on (love it). I have used my clamshell and cat dies. I can't wait to use the owl die as well as the blazing star.
I would also recommend picking up a copy of Ebony Love's book, "The Big Little Book of Fabric Die Cutting Tips." She describes the different dies and other things for using the machines and dies. It has been a help to me.