I think l like the jumpsuit better, just for practical reasons! It seems like it could work well for summer with some sandals or flats, but could also be layered up for fall.
I really love the look of the dress, but I am reminded of how I'm almost always too hot in public venues where music and opera events are held--they seem to crank up the heat like crazy, and I imagine myself sitting there up to my neck in wool, and it ain't pretty :). But maybe you run cold and/or your venue has reasonable levels of heat?
ETA: In answer to your original question, I think it's a matter of how much you love these pieces in comparison to the unknowns at NAS...bird in the hand vs. two in the bush kind of thing.