It's too bad that we can't test drive each motor before purchasing. Since I get the opportunity to ride in a relatively wide variety of vessels, there is one difference I really notice from motor to motor: noise at cruising speed. The 4 cylinder Yamaha engines are obnoxiously loud in my opinion: makes it very difficult to have a conversation at cruising speed. I know the Yamahas are popular, but I cringe when I see Yamaha's on a tender, knowing it's going to be an unpleasant, loud ride out to the ship I'm servicing. So to me, a quiet motor is king: Honda takes first place in this category, Mercury also very good. When you have a long trip back to port, a quiet motor that allows you to have a conversation at normal volume levels makes the trip a pleasure.