Conclusion
Given the rosters under their control, I would venture to guess that Vigneault will be the most succesful, with Tortorella a close runner-up.
Eakins has the best chance to grow with his team, while Roy will find some adjustment. The most interesting pairing might be Ruff and the Stars. Such a veteran coach behind the bench of a young squad will provide an interesting dynamic, and will be fun to watch to see how both sides adjust to the new situation.