Well, technically... X-Plane also has real world weather, VATSIM support, and I think it's possible that it has more airports then MSFS, but I'm not sure.
Something that X-Plane has that MSFS doesn't is an included airplane editor, and there are hundreds of planes available for it, many more then for MSFS.
Don't get me wrong, MSFS is nice, but I feel compelled to correct some misconceptions.