Since I ALWAYS chime in on these threads ...
We have now completed several trips with a Thetford cassette and are simply weeping because our truck does not have the space to rip out the cassette and reinstall the Natures's Head!
The cassette requires more work and chemicals to remain odor free and while you could dump it in a rest stop toilet, the stench would make you VERY unpopular. :-(
As Joe917 noted, the Nature's Head is fine in a wet bath as long as the seals are intact - not hard to do. I drilled the same holes that he did.
It is certainly true that about 25% of the drying medium is not stirred by the agitator - round agitator, square box, this does not really limit the toilet. Two people are still going to get two to four weeks between dumps. And the urine bottle is easy to dump at a rest stop. ;-)
WAY to much misinformation around. Listen to the folk who actually have one.
Final shill: Larry, the owner of Nature's Head answers e-mails and really wants you to be happy with his product.