As a GTD-to-Autofocus switcher, I certainly wouldn't say it's a complete miracle, or definitely better than GTD for everyone, or anything like that. But if you read the instructions fully, it is much more sophisticated than some of the replies here give it credit for, and it is certainly not based around the idea that if you don't feel like doing something, just dismiss it from your list!
AF merely provides a very different, and arguably simpler, set of answers to many of the problems DA identifies. For example, take the idea of "next actions". In Getting Things Done, as I'm sure we'd all agree here on this forum, Allen hits the nail on the head when he says that much of our stuff doesn't get done because the things on our to-do lists are not physical next actions. But his solution to this - separate NAs from projects, and make sure all NAs are really next actions - turns out to be only *one* solution to the problem. AF uses a different solution: "closed lists", whereby on each page, as the range of options progressively narrows, one will eventually be required to turn "undoable" actions into real next actions. There's way less overhead in terms of time spent maintaining the system, and more flexibility in terms of deciding in the moment what the next action really should be, rather than what you thought it should be the last time you did a review, or added a project to your list, or whatever. Getting back "on the wagon" is also so easy as to not really exist as a concept; you're always on the wagon really.
It is, however, a *total* mind-f*** for established GTD users, because at first it seems to violate all GTD's principles. Frequently, I have items on my single AF list that are next actions connected to a project, and also an item that is the project itself, and also waiting-fors relating to the project, and sometimes even random questions that I'd previously have put in project support material.
I'm not coming here to post on the Davidco forum to try to encourage people to abandon GTD. But really thinking about the AF principles and ideally testing them for a few days will, at the very least, hone your appreciation of WHY you prefer GTD, if you do.