Dry Composting Marine Toilet?

[Simes]

All I ever seem to do is post questions for you folk to answer, and here I go again.
We are going to have to fit a new heads system in the very near future, now I was going for a Blakes Lavac with the big pump and a big holding tank, new through the hulls and pipes, going to cost a pretty penny or two. SHM is also not happy with the thought of several gallons of "Black Waste" and the potential for disaster that this brings with it.

So I have been looking and thinking about the "Air Head" or the "Natures Head", lots of advantages and only a couple of disadvantages.

Are any of you good folks using one of these "Composting" systems?

How good are they really? Do they still work when the weather is "Off"

Many thanks

Simes