jmf,
I've used both the 3pt and hitch type (with wheels) box blades on ag tractors. I much prefer the hitch type.
I've been keeping an eye out for a deal on a box blade for the Toolcat but I am only looking for models with wheels. My use would be on gravel or dirt and I think the wheels would provide better depth control as well as cushion the gouging affect on uneven surfaces. If I were going to use it on hard surfaces for pushing snow or manure I would look for one without wheels.
dsb