I know many of the people on the David Allen team personally and I can say that they are a sharp group of intelligent individuals who are skilled at showing people how to get things done. Unlike a public seminar, where you will learn how to implement the David's GTD methodology in your life, in the workflow coaching you will experience what it's like to actually get things done while learning how to sustain the process.
At the risk of sounding like a commercial spokesman, I'll stop at this: I think the workflow coaching is an extraordinary value. The opportunity to enter a contest to receive this coaching for free is almost unbelievable. The contest ends tonight. Details here.