After a few months, could you report on your experience with Organize? I'm getting my iPhone tomorrow, which puts me in the category of folks looking for solutions to Windows computer with outlook/exchange and iPhone for my GTD system. After reading this thread I'll look at Toodledo and Things, wondered what you thought of Organize since it's the first I've heard of this one.
I have been using Organize HD from Taskfabric, very nice application. It is very similar to Omnifocus, and it synchronizes well with my iphone, ipad and home pc. It has a nice feature were you can create tasks from your emails, and also can interact with your calendar (with some workarounds) so that your task can show up as calendar events on the day you need to review them. It does provide good reviewing tools, and you can define contexts and sub-contexts. Overall a good application, nice visual interphase, but poor at creating reports.