I found the set up this plugin quite easy and intuitive but that's where user friendly experience ended.
The standardised widget identifiers were used so when inserted into the sidebar none of the stylings carried through.
I don't fully comprehend the usefulness of having a description input but not a title input. HTML can't be written into the description area so that doesn't work as a solution for styling.
I think with a bit more follow through this could be quite handy as there is a lack of Mail Chimp integration widgets on the marketplace. For the time being I'll just grab the embed code form Mail Chimp and insert into a text widget.