For me I really enjoy WDW's version as well, personally I've yet to experience a rough ride which I've heard many folks say it has, but that's just my experience. That said, it does need a top to bottom refurb just for the simple fact these are the second-oldest coasters in a Disney Park, they need the refurb regardless if one finds them rough or not.
DL's Space Mountain is fine...unless it's Hyperspace Mountain, then it becomes my favorite stateside Space Mountain *and* my favorite Star Wars ride.