Okay heres my take on the subject.
I've used all three main types of Thetford loos over the years heres a few helpful tips
[ol]
[*]I find they only leak if not pushed home fully
[*]Clean check and grease seals a couple of time a year
[*]Always open the blade first, lets the waste away quicker.
[*]If we get a paper jam then it's dam near imposable to get the cassette out till its cleared first.
[*]Loos are fine to use for number 2s just don't use wipes
[*]Don't buy the expensive Thetford paper we have tried lots and find one of the best is Andrex Classic much cheaper and dissolves down well.
[*]No need to lay paper over the blade this can cause paper jams just open the blade before use, number 1s and 2s
[*]We got a second cassette, with 6 of us, 4 kids using at night I got fed up of having to empty the cassette at 3 or 4am (Dad the toilets full. ) Even after emptying just before bed time.
[*]Don't buy cheap chemicals from places like Aldi there a lot thiner don't go as far and don't dissolve the paper as quick plus the Thetford pink flush is supposed to have a lubricant for the water pump, have heard stories of the pumps gelling up solid after using cheap brands.
[*]Start to empty cassette before pressing the air vent button, I learnt this lesson when I pressed it a little quick before I had lifted it high enough and got my hand covered in poop.

[*]Full strip down once a year you wouldn't believe what gets behind the seals, scum, scale, poop, to name a few
[*]Empty water tank before winter storage.
[*]Bribe the kids to empty the cassette.
[/ol]
There are a few ideas but there are no real SET rules just use as you see fit and what works for you.