We have a Fiamma Bipot. We purchased one of the models with the larger holding tanks, because it is taller. Makes it much easier to get up & down. We chose our model over the Thetford, Century, Visa, Sealand, Passport & other more well known brands because of two reasons - - price & design. Found it online at a discount, and we couldn't be happier.
Due to the nature of this particular product & its known use, we wanted something as simple as possible. We found ours is about as easy as can be. Both the top & bottom halves are single units. They each have a cap on the back, and are held together by two stainless steel clamps. Fills easy, works perfectly, and extremely simple to empty. No mess & super easy cleanup.
Coleman & Camco both sell a very similar design, and they seem to be getting descent reviews as well.
We couldn't be happier. Good luck with your search!
We have a 1994 Viking SP195 popup. We're the third owners. It was garage kept with the first two owners, so it's in really nice shape.
We thought about adding roof air, but since we don't camp in the HOT TEXAS HEAT, we decided not to invest the $$$ in buying & having roof air installed.
We purchased a portable A/C unit and have used it several times. It cools just fine. But we've only used it in early Fall and late Spring (when things were still a little warm & sticky). It worked just fine. The only real issues we had were user errors. (it has a LOT of extra features, and we simply wanted to turn it on & let it run. It kept trying to run one of it's "programs" - - ARRRGGH!!!)
Anyway, we just place it on the back counter. Our canvas zips together in pieces, so we just unzip a section in the top back corner & vent the hot air out! Works perfectly. We also have a condensation hose that runs out as well (just to play it safe).
We bought the Popup Gizmos for the bunk ends which makes a HUGE DIFFERENCE in the inside temps in our popup. Put them together with the portable A/C, and we were fine.
Frankly, the roof A/C will probably freeze you out if you leave it going all the time, so that can be really nice to have if you're camping in warm/hot weather. We just didn't want the expense for something we won't really use very often during our Fall/Winter/Spring campouts.