I think the largest advantage that SpaceX plan has over the proposed is safety. With SpaceX, you never have to enter or leave the ship in space. Docking takes a while (Soyuz takes ~2 days to dock with the ISS, it’s a very slow, very dangerous maneuver) I think avoiding this docking procedure makes SpaceX’s plan…

Look at that! It’s a Honda Impreza STI!