They are noted for working fine in tourist areas, and badly in homeless areas. Making them big enough for wheelchair accessibility makes them big enough for drug deals, too. They're also far too expensive. The cleaning machinery is standard industrial automation equipment from Telemechanique. I've seen one opened for servicing. If you built a washing machine that way, it would cost $20,000. It requires power, water, and a phone line.
There's the Portland Loo.[2] This is designed for maximum homeless proofing. Graffiti-resistant. Gratings at top and bottom instead of solid walls, for reduced privacy. It's not self-cleaning, but can be hosed down or pressure-washed. Only needs a water line; power requirements are low enough to be supplied by a solar panel. “It’s not supposed to be a comfortable place” - Portland Loo sales manager. Seems to work, but $500,000 installed is a bit much, even with all that heavy stainless steel.