I have read some things on it. Also, they offer some free webinars through Microsoft (using Outlook with Mission Control).
In a nutshell, my interpretation is that you have a list of stuff you are "Not Doing Now" and a list of "Never Doing Now." My take is "Never Doing Now" is "Someday/Maybe" and that you look atthe "Not Doing Now" list to pick things to put on your calendar. The big philosophy difference is that everything is put on the calendar. The way things are put on the calendar, is that you block of time slots for certain activities (such as checking e-mail). I just don't see it as handling the details.
Also, I called them one day to ask for a description of the model. Whereas you go to David Allen's website and you get a great deal of the methodology up front for free, these folks were pretty secretive. For example, when I asked what the "Not Doing Now" and "Never Doing Now" was all about, I couldn't even get a decription of them.