I was thinking about putting one in our 21 Escape
, but after measuring the door and the measurements from their website, I realized it probably wouldn't be able to get inside. Probably would have had to flip it on the side. I contacted the mfgr/dealer but they never got back to me. Decided if they weren't interested in contacting me, I wasn't interesting in flinging money their way.
if your problem is dumping the tanks - you get used to it. yeah, the smell isn't the greatest, but if you're not smelling yours when it's getting dumped, you'll smell someone else's (depending upon the wind direction). Can't avoid it at campgrounds with full hookups. Or at dump stations.
I got a little folding step/seat off Amazon that I use when I hook up and it's great. Much easier to put the sewer hose on while sitting on it instead of bending over that far down.
Ick alert (for some)! If you don't want to dump the black tank as often, don't put your TP down the toilet. I have black plastic bags that I use for the TP that I knot up in an easy to release knot/tie (never was a boy/girl scout so don't know the name of it) and hang off a Command hook I put under the sink. Bag gets tossed as needed. Works great for me.
One of the reasons I was looking at a composting toilet is that I was real tired of the smell in the bathroom of the 21, especially when I pulled into a campground. It was really bad, even if I had just dumped and flushed the tanks. Turns out it's the crappy (HA!) vent cover used by ETI and it's a well known problem with that size trailer. Doesn't work worth doggie-doo-doo. I replaced it with a proper vent and now the smell has gone away.