Thank you to everyone for your time spent helping us with this. You have all played a big roll in our decision making. After a long and very difficult process we have made up our minds. We are going with the Hallett 275 w/ Merc 565. If I could have the 600, I would have went that route. We felt that the overall length of the boat would probably be a better trade-off than my desire to go faster. I think it would be better for the kids too. I'm sure the 565 will be plenty fast when the wife lets me do a speed run. I'm a little sad about the 600, but I think we made the right choice. I sure love them 255's though.