We installed a Bosch right after buying Worldwind twenty years ago.  It was the only one rated for marine use.  Three years ago we needed to replace it as corrosion had finally taken it's toll. The new one is no longer UL listed for marine use.  I didn't think it would be a problem until I recently had a survey for insurance purposes.  I won't go into it here as this was only one of the idiotic things that came up, so beware when you get a surveyor, a lesson learned.  We don't use it for anything other than showering as Julie still heats water on the stove for.  Using it for hot water in the galley would use to much water. It's wonderful to take a warm shower after a cold day out on the water. We anchor out as much as we can which is most of the time and in the northern climates it's a real joy.  The downside is water use goes up, but we have a water maker.

Some cruisers I know are using one called Evoirtech? or something like this, found on Amazon.  It's about half the size of the Bosch but isn't rated for indoor use and doesn't a connection for a vent.  They make a small hood with a vent for connection.  I've heard from two cruisers that they're working out quite well.

In warm climates when we were cruising we rarely used it.  I doubt we used it half a dozen times in two years.  But in northern Calif. we use it all the time.

Jim