We have been seriously looking at retiring to canal boat, cruising the UK canals in summer. Doing my homework on these I have learned a lot about off grid living since they have to be fully self contained if you are not going to live in a Marina. Most have solar power and a battery bank, inverters for 110 Volt. Of course sewage is an issue too.
One of the things I learned about was the cassette toilet. They are popular with boaters. There are places along the canals just for emptying these as well as topping off with water.
Since our backup plan is extending camping trips out west we have been looking at boondocking and a cassette toilet seems like a good option since you can empty one into a public toilet. Seems the biggest drawback is without the proper chemicals, the smell when you empty it can be pretty horrific. But boaters seem to have figured it out. Then of course some people have a real aversion to handling a tank full of sewage, which I get.
Curious if anyone has installed one in there camper? Seems to me if you can deal with handling the cassette it offers some advantages.
We use the traditional porta-potty (one gallon or so a day) and it can be tricky to empty. I do it in the campground bathroom and strive to do it when it's very late. I'm very careful and never spill a drop but I can see why camp hosts don't like it. The the tank above needs a pump and dump station.
Cassettes have been around for many years, mainly in smaller truck campers and pop ups. They are similar to a Porta potty except you don't handle the top part of the potty to dump. I say pick a toilet that is more compact and easy to handle. Check into the Curve.
Also keep in mind that the more capacity the tank holds, the heavier/more awkward it is to dump.