I have a 6' KK tiller that has made it through its 4th season and is holding up very well.
When I bought it, I was concerned about the "advertised" 8" working depth since the tines only extend 3 or 4 inches past the skids when set to the deepest position. I called KK and asked to talk to a technician, was told the working depth is based on multiple passes that allow the skids to sink into the ground.
The KK is advertised as being Quick Hitch Ready, but the hooks on my Speeco QH wouldn't fit between the pins and frame of the tiller. My blue tip wrench made quick work of adding clearance and all is well now.