"unpopular" ? According to "who".
Personally, I don't care if it is a Raven, Hardbody, Fathom or Haunted House. It is the "journey" from buying a filthy dirty and unloved pin into a restored and fully functional pinball. As long as it is almost complete, it hits and queue and waits it's turn.
Enjoy the process and the play time. If the machine is a Holy Grail or keeper - who cares how much you spend ? You will always at least "break even" if you want to sell further down the track.
