In some floor plans (those with 2 bathrooms) the vacuflush system is the best way to handle waste and keep 1 black tank. Another benefit is that the tank can be placed just about anywhere and that helps weight distribution.
Ours has been relatively trouble free for 13 years with the exception of having to do a bellows replacement last year. That is a pretty standard expectation for wear and tear for this part.
When we bought this motorhome, we thought the 2 bath was a little excessive but we loved the floor plan. After living with it for 13 years we wouldn't be without a 2nd bath given a choice.