I got the 4120 last year with 400cx and love it... No regrets, plenty of power, I would only step up to the 4720 if I wanted to run a small bat wing.
I second the motion for the aux hose kit for the front end, it will allow you to use a grapple, or a 4 in 1. I just purchased the kit from JD and am saving my money for a grapple.