We purchased our Airhead when we moved aboard about 1.5 years ago. It's been great. We've shown it to several other boaters, of which one purchased the Airhead, the other purchased Nature's. When we were looking, the Nature's head top came off to drain the urine tank leaving the composting bin open. Yuk, not for the squeamish people. Check that feature before deciding if you can handle the Yuk factor. The Airhead is smaller as mentioned, better for short people.
The Airhead urine tank is a separate unit that unbolts from the front of the system, not having to open the compost bin. Buy two for the time you forget to empty the tank and have to go in the middle of the night.
Also, spraying the bowl down after each use keeps it from growing mold and germs.Daily cleaning is easy, I use Lysol wipes. Filling and wiping the urine tank with white vinegar helps keep the stains from building up when the monthly deep cleaning time is due.
One last comment, I found sugarcane toilet paper. It's 80 cents per roll, composts very rapidly, in a matter of a few days actually. Check the internet for it, and it's much cheaper than the expensive RV paper.
John is the person in charge of the cleaning and maintaining the head, I can only attest to the use of it but he'd probably agree with purchasing Airhead over Nature's.
Diane Clark