I'd say Bisu would beat Free in a Bo5. PvP is Free's worst match-up and hasn't played it well lately. Bisu on the other hand played a lot of PvP. He was pretty even against Stork and beat Much, Kal and Backho recently.
Interestingly enough he lost his last three Proleage games against Free. But then Bisu hasn't been great in Proleague in a pretty long time.
Bisu will beat Free or Nada. No questions asked.
When I sought altruism, I found charity devoid of conscience.