My (new to me) boat came with a dishwasher. I can see a potential advantage to having a dishwasher in that it might use less fresh water than some people would washing
a full set of dishes by hand. On the other hand, in order to run the dishwasher I have to run the genset for an hour and a half. In that same time with the genset going, my water maker would make 60 gallons of water -- certainly more than anyone would use washing
a set of dishes. I guess this is a round-a-bout way of saying I don't see a lot of sense in a dishwasher on board, but I have one. Perhaps someday I'll swap it out and put a trash (not garbage!) compactor in its place. That would be very useful.
As far as brands, mine is a fisher-paykel. It is ok. My wife had a fisher-paykel in her former house and hated it because it was always breaking down. Given one neutral and one negative between the two of us, that is a mild thumbs down.