Both of these would be great boats for cruising. You can go around the world with either one, given proper preparation.
I have sailed the Beneteaus 40, 43, and 50 from that generation, and they are not as performant as the very newest Beneteaus, but have stayed some of my favorite boats out there, great quality/price balance. I love the open
cockpit with the twin helms, love the layout. I personally don't think the DS are as nice for cruising; they emphasize the aft
cabin, at the expense of the
cockpit; access from the cockpit to the the sidedecks is more difficult because the cockpit has a round, big enclosure which is hard to walk over, epsecially when heeling. You simply don't spend that much time in your
cabin to justify it, in my opinion and experience as a cruiser.
The Dufours have a reputation as being a bit higher end than
Jeanneau or
Beneteau, a bit better built. They have been making great cruising boats that have also been designed by racers, and also have a lot of good
single or under-handed capacities.
The edge in your case goes to the B43 in my mind, because Beneteau has the best resale value of any brand out there.