I think that any tool that helps is a good thing, Scott Ostrander, but a living, breathing, professional editor / copyeditor / proofreader beats them every time. Those applications go by the rules, but they can’t ask what your intentions are or who your audience is, and sometimes they just plain insist on following a rule that doesn’t work in a specific post.

But good for you for using it; it speaks to your professional outlook in an excellent way.