We just purchased a sailboat with a brand new composting head. Since a boat is much more confining than a house, I was concerned about odor. Research followed. Read the reviews on the posted links below for more info, but almost unanimously sailors using marine composters loved them and preferred them to conventional marine toilets.
I should be able to provide more information after using one myself. From my past experiences with marine sanitation systems, I'm thinking I'm going to love it.