I bought a Houle TS 15 tree sheer. I have already cut down about 800 trees. It works great. I can rotate and use it like a grapple to move and stack trees.
My favorite is the ASV RC30! I am up to 15 attachments as soon as I get the trencher put together. The RC30 is like a swiss army knife, just open to the right blade, and it'll get the job done!