For me, it is still the best of solutions, despite the gas issue. No waste on board, no odours, and no dealing with disposal.
It is an expensive option for sure, and the decision was the lavatory or Lithium batteries... I'd rather change the batteries after 2 years than cart cr*p around with me and have to dispose of it regularly.
If toileting on the vehicle is not negotiable, then you have me absolutely won in terms of the acts of both performing natural duty and dealing with the aftermath.
I don't particularly baulk at the cost but am eager to learn how it works in the field in terms of gas consumption, reliability, noise and overall practicality.