We use ours quite a bit (please hold the snarky comments).
Our walk through layout puts it at the far rear passenger corner with a nice view out the back windows, which are pop outs for that fresh air feeling, and tinted for a bit of privacy and sun protection for those special parts. It all works pretty well. It is even usable at 70 mph on the highway (use the window shade if truckers are around)
Since I am the designated PP manager, and we go on six week van trips, I (we) have learned a lot and have user rules:
1. It is there for convenience, so if an alternative depository is readily available, use the out of van facility (minimizes the PP Manager's efforts)
2. If #2 is the calling, then use a Happy Bowl liners (may not catch it all but it will catch far more than not using one), deodorizing drops (crazy what two or three drops will accomplish), and PLEASE disclose what is brewing and about to happen so the other person(s) can prepare and go out for a walk. Also, open some windows and use the Deodorizing spray (in addition to the drops), if needed. The bowl is to be left super clean, nobody else cleans up anybodyelse's stuff.
#3 If we are going through elevation changes - leave the blade valve just ever so slightly unlatched a bit to allow for air pressure changes.
For the PP manager:
Always use good quality and and quantity additive in the holding tank, do not short change this. Make sure to always carry a new bottle as back up. Make sure there is enough water added to the holding tank to cover the bottom to begin with, as well as enough water in the upper supply tank.
Make sure the PP is secured so it does not tip over while driving. It is never a good thing to hear a sound, look at each with the "What was that?" look, look in the rear view mirror and realize the PP is over on its side and loose. I have had it happen. FORTUNATELY, nothing has ever leaked out, but it is a high stress inducing moment.
Emptying the holding tank - Any bathroom will do, but if the tank is really full, it is going to be heavy and it is not going to be pleasant (btw - picking up steaming mushy dog (big or small, but bigger is worse) poop isn't pleasant for me either, I put them on about the same par). It is really good if there is fresh water available to do a couple of rinse outs before adding the Holding tank additive to the now empty tank. If not, then just make sure there is enough extra water from somewhere to add to the holding tank and additive. Having a dedicated one gallon jug for PP water transfer needs is handy. Trying to add water to a PP directly from a drinking fountain is NOT going to go over well with anyone, and is not even good for my own mental health.
Hand gel and disinfecting wipes are really nice supplies to have on hand.
We love ours and consider an essential piece of van equipment.
Okay, need to go pack up some swivel bases for the rest of you. Maybe a swivel base for the PP, hmmmmmmmm.