we have a sea recovery Aquamatic 900 on the 70 footer I run, they make smaller models.
it's fully automatic, even the weekly fresh water flush. controlled by a touch screen. So far so good after a year, only issue is that the standard filters are a bit small and clogs a little too quickly up north, even with a plankton filter. but that's an install/option issue, not something related to the WM.
dont' go to small since you will typically need to run the genny to make water, you don't want to have to run it for 6 or 8 hours a day...
it's a must have for anyone going to the bahamas since water is so $$ over there.
on teh downside, the aqumatic are not cheap due to all the sensors, electronics, etc...