I consider the standard 40l aquaroll to be a near perfect bit of engineering. (I also have a 28l one, but it mine has the disadvantage of only having a filling aperture in the upright position. I also find it less easy to wheel than the larger 40l).
In contrast I find the WasteMaster very poorly designed.....its only virtue being the low height which (usually) allows it to slide under the caravan. It is very badly balanced when full, and wheeling it any distance is extremely heavy work. I use mine mainly as a trolley to carry the toilet cassette!
My ultimate solution will be to use a small bilge-pump to either pump wastewater to a hedge (where appropriate) or into a designated waste aquaroll.
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