Difference between Punisher, Winter Soldier, and Black Widow?

I was thinking about getting Punisher or Winter Soldier with my 400 ES. I already have Black Widow, is there a difference between the three or are they all pretty much ranged gunner heroes? If I own BW is there a reason to own WS? I feel like Black Widow and Winter Soldier share the same kind of stealth mechanic, I think.

If they are similar I might end up getting Luke Cage or Cyclops (is Cyclops even fun to play?)

Thanks!! :*