So the only thing I will say is that the problem with a "DocuSign" alternative is that docusign is more accepted within the proffesional community and when docusign says something was signed it's trusted. In this case what is to say you don't modify the data or something similar, I know you could send out a confirmation e-mail or whatever but you get my point.
But ofcourse I will always take more apps that can be selfhosted :D