i think the walking best is still going through growing pains, it didn't make it much farther than off the trailer in 07, But like any experiment in mechanical motion there is lots of R & D that will need to be done over the course of much usage time, and if the guy only drives it a hand full of times a year, then it will be awhile before the walking beast is somewhat reliable.
personally I prefer the mondo spider,
http://www.mondospider.com/ same kind of machine, but way more complex with it's articulated movement, and it seems to work allot better, but nowhere near as big..