I would say that the difference is between a "constructed" language and a "designed" language, both may be "invented", but the latter (Esperanto) simply is on a

I would say that the difference is between a "constructed" language and a "designed" language, both may be "invented", but the latter (Esperanto) simply is on another level. And this opens the doors to debating whether or not Esperanto was well designed or not.