It works exactly as advertised, so just do a good job of reading the advertisement before you buy.
That sounds strange, allow me to explain.
Basically, the GTD plug in does everything that the web site says it does, and does it exactly the WAY that the web site says it does. Therefore, it works exactly as advertised. This is more then you can say for most software.
However, the thing to keep in mind is that it doesn't really *do* all that much... it is a very simple program designed to make features that Outlook already supports more readily apparant, and more elegant. People who are expecting a silver bullet will be disapointed-- that's not what it is. If you are expecting the GTD plug in to add a bunch of new functionality to then you are not going to be happy. However, if it is important to you (as it is to me) that a tool be highly customized for your way of doing things, the plug in will make you very happy-- it is very elegant, and makes implementing the GTD system far more intuitive. You feel like you are using a tool designed speciffically for GTD, instead of shoe-horning the GTD methodology into a more generalized tool.
Bottom line: I really like it. It is very nicely implemented, and it works very well. It makes tracking certain classes of items much more intuitive, and (this is important: ) grafts GTD terminology into your primary digital workflow tool.
Also (because it doesn't really change the way outlook stores the informatioN) it syncs well with PDAs. I have a PocketPC, and the transition was totally seamless.
There are a couple minor bugs (the toolbar sometimes disapears in windows, and you have to click a "refresh" button to get it back) but it is well supported, and there are workarounds for everything that is wrong.
I think that if $50 isn't a lot of money to you (and for most people on these boards, I suspect it isn't) then buy it. However, if $50 is something you have to think about first, then read the web site. Go through the demonstration. Then read it again. If it still sounds good, buy it. The idea here is make sure you understand what they describe, because they are not over-selling it-- it is exactly what they describe. However, when you really understand what they are describing you'll realize that it isn't that big of a deal.
The plug in won't part the red sea... but it will help you get your GTD system more elegantly integrated into your tool of choice. (Outlook)
--- JRJ