Hi, ... as much as I like Xfce, the best window manager of all time is Echinus.
JWM is another all time favorite, however, it lacks the drag and drop feature to be a complete desktop. The combination of the 2 with Xfce functionality would be ultimate. Imagine something like that with Mate's mature Gtk shades and colors! It would be beyond Mate, it would be ultimate, in terms of speed and efficiency.