I've never seen the walker model but even the one with the six big balloon tires is pretty awsome to watch. the arm grabs the trunk then saws it off below the grab. pickts the tree up and runs it back and forth between the wheels on the grab arm debarking and removing the limbs, then stacks it off to the side.
in a matter of a minute or so it's changed from a tree to a log.
sure glad I'm not a logger. those guys never had it easy, and it only seems to be getting worse for them every year.