IMHO the SD is a very solidly built watch, i.e. a real tool watch. I regret selling mine off in the 90's.
OTOH the latest ExplorerII appeals to me as I like the freccione GMT hand, to me a quantum improvement over the skinny hand on the older Explorer II, which I also owned and disposed after awhile (each man to his own- some hate the newer freccione hand)
Since you are not looking for a real tool watch that can take punishment, I'd take the Explorer II which comes in handy for travel as well.