Isn't it, though! The one area where it falls short for me (and I should stress that this is OmniFocus that is deficient, not Curt's script) is that there is no good way to put in relative dates. That is, you cannot specify that action B is due 3 days after action A is completed, or action D starts some number of days after action C is completed, etc. I have to resort to things like following action A with an action that says "set due date for action B" and hoping that I do it promptly.
If you think it would be useful to have built-in support in OmniFocus for relative dates, use Help->Send Feedback to get your vote to the developers.