I have it done every year at the Brittany trials in January near Sonoita AZ.
One thing to be aware of, is that I have never been able to get the tanks as empty as I normally do with a regular dump. But it is enough to get us by till we go home, and I don't have to break camp to go find a dump station. It saves probably the best part of a days labor for us, so it's well worth it. A lot of people gripe about the price.. I am happy to pay it, and tip very well. These guys remember me, and will look me up to make sure I get my tanks emptied... Nice as I may be out busy with dog activities. They have even come out special for us when I called them once.
Treat those that take care of you doing unpleasant work well. It really does pay dividends.
