Has anyone tried or used a composting toilet?

I was reading about it today, enjoying my day off, and after looking at a
video clip of the Sun Mar systems it sounds pretty good for a small house
with limited waste connections. My house has only 1 bathroom, kitchen sink,
and laundry room outlet going to my septic tank. If the toilet could be
converted to a composting model, that would mean the septic tank would be
for greywater only - dramatically increasing its lifespan and its doubtful
I'd ever have to pump the tank again.

I've never priced them out, so they could be 20 million dollars for all I
know, plus I would expect the county makes it tough if not impossible to
install them in a residential area. Heck, simply having a septic tank is
almost an impossibility now.