Agree with Job, in general. There certainly are better tools out there.
Symphony’s strength is that you can do some very precise and sophisticated color correction within the Avid itself, often in real time. Depending on the type of programming and your workflow, that can be a very big deal. FCP (legacy or X) or Premiere can’t really do that, even with plugins. The $3k pricetag is kind of hard to justify these days, though.