There is a significant difference. If Madara is alive, he can be killed in one go. If Madara is an Edo, you can't just kill him, you have to seal him, which is a lot harder.Madara is dead, Edo-Madara is just bound to a host body and his soul is forced to walk and fight; Really there is not much difference it's still him but more like a Zombie and he gained his power from before he died so he really is just testing his new found power right now in the manga prior to Edo he just awoken the rinnegan and implanted the 1st hokage's cells then he died off.