I had a C-head toilet in my 13 foot Scamp
. It had the privacy room, but no shower or toilet installed. I used it for three years, taking it to Florida for 2-3 months in the winter. I was very happy with it. One time while in Florida, I did get some knats who took up residence. Simply changed the compost medium and the problem was solved. Another option, according to the manufacturer, is to place a small piece of a "No Pest Strip" in the toilet housing.
There was never any odor, other than the urine container (gallon milk jug) if you didn't empty it every other day or so - extremely easy to do. Some folks use various chemicals or vinegar or a bit of dish soap to counter the urine odor. I just emptied the container every other day.
I did not bother to install the vent tubing. Since it was just me, and I did not use the toilet 100% of the time, the contents dried quickly with just the cocco coir medium.
I was so pleased with the toilet, that when I ordered my new Scamp
16 foot #4, I ordered it with the side shower, but no toilet. I will get another C-head to install. If you get the optional rubber latch kit, the entire toilet is extremely simple to remove from the shower when you want to use the shower, giving a much more usable area in the side bath model. It is still short, but plenty of room otherwise.
When I first got my old Scamp
, it had a chemical toilet. The C-head upgrade was a big improvement, and eliminated virtually all the odor. One person using it for night and "quick" use allowed me to go four to six weeks between emptying the solid container. This is also a very easy, not gross process, accomplished right at your campsite - no hauling out to a dump station or lugging the chemical toilet to a rest room.
In fairness and full disclosure, there are two drawbacks that I found.
1) Occasionally, if you are less than careful, you can sometimes soil the agitator mechanism. I just check after use and wipe it with some toilet paper if it happens.
2) A composting (actually, technically, a dehydrating) toilet does not handle vomit or very watery stools very well. Line the toilet with a plastic bag if that is a temporary problem.
If you want any additional information (heaven forbid I haven't been graphic enough!) just ask.