Thanks for the input. I did go ahead and buy the Dufour 455 which I will be taking delivery on in Chicago and then sailing it back to Bayfield, WI on Lake Superior in early summer. As has been discussed so often on this forum, there are so many variables when considering a new boat, and it is a matter of picking the one which best fits your circumstances. For me, the deciding factor was that my wife loved the boat and basically wouldn't listen to me when I told her about some other similar and nice used boats (am I lucky or what? she wanted me to spend MORE on a boat). I have spoken with a lot of people with direct experience with these boats who felt that the quality was excellent and perhaps better than some of the other production boats.
I also really loved the Dufour 44, but my wife not so much, so we compromised.