GAKESMITH I have been using the 1.2.22a alpha version and it has worked flawlessly for me on OS 10.5.1. I tried iGTD and OmniFocus for several days and now have gone back to Ghost Action. I find it much simpler and more reliable, especially syncing home and office computers using .mac. (Version 1.1)
PROTEASOME Excellent application. I've been searching for a similar app for a while now. It's basically an advanced todo app with a simple interface and that is sync-able over several computers.
Well done, however the price is a little steep imo. (Version 1.0.1)