These represent two equally reasonable (IMHO) opinions of what “Move Face” should represent. Apparently each program interprets it in one of the ways (I’ve never used SU). I wonder how many SU users are complaining it doesn’t work like Rhino.
I think that Rhino’s way is truly how “MOVE face” should be interpreted. I also think that Rhino should implement the other alternative as well; I’m just not sure what to call it. “Move slice”?