Tried one but it was a bit long-winded, TBH. In cases of mudzilla, I pop into the local coin-operated jetwash on the way home and spend 50p for a thirty second light blast-over. Works well if you click your SPD shoes into the pedals.
Only from about 2-3 feet away and just to get most of the mud off before I get home. Most times I don't even take it off the rear rack!