To me, GTD apps used to be worse than Twitter clients on the iPhone before Tweetie: ephemeral.
Yes, even worse than financial apps: I didn’t know how to choose one and keep rolling with it. You know - that new kid on the block could be better and has a beautiful UI. You know the drill. I was a GTD user who couldn’t manage to find an actual GTD to get going with. To better understand the situation, it’s important to specify the workflow I used to have, and the one I have now. Before the iPad came out, I organized all my tasks and projects on my Mac (whether in a desktop app or online service) and didn’t really care about achieving a cloud-based workflow. I had an iPhone (a 3GS, to be exact) but I just didn’t see it as a device to carry my GTD database around. I tried Things, iCal to-dos, Basecamp, Backpack - all sorts of productivity apps / project management tools out there. None of them survived.