If they're frustrated with Sublime with practical reasons (i.e. performance, plugins, extensibility), I don't think Code or Atom would satisfy them any better. You could make the argument for vim or emacs there, but those have been around much longer than Sublime, I doubt Sublime's eating much into those users in the first place.

If they're frustrated with Sublime due to not being FOSS, nothing I guess. But again, those people would have largely switched over already.