I've been selling RVs for 10 years, have camped in MH's , TTs, FWs etc. The Thetford 402C cassette in my Jayco, in my opinion, is superior in most ways to the standard black tank setup in those other units. In a standard black tank setup you have to add chemicals and water to tank before you ever make your first flush. You also have to create an agitation mechanism to thoroughly clean the tank after use - by means of sewer flush, driving around with ice in tank, etc. Also, if you fill your tank and have no sewer connections at your site, you have to load your stuff and move trailer to a central dump. With the cassette, you have a flush water tank that you can load up with chemicals. Every time you push the button on the toilet, wonderful blue water fills the bowl with sanitized goodness. Once you fill the tank, you can load in truck and take to dump. You can then rinse/shake as much as you want quickly to completely clean the tank. There are no smells in camper when used properly. Most important, because you have more physical control over cleaning the tank, there are no smells after pulling the unit from storage.