I have Todo from Appigo ( http://www.appigo.com/todo/mac ) and I'm learning GTD. Do you think Omnifocus would bring much more that what I have ? It seems interesting but it's still quite expensive even at 50% discount And iPhone version is not discounted
I switched from Todo to OF three months ago. It is worth every penny for me, even at full price. Todo would be fine if you don't need to manage lots of different lists. Also, OF is a WAY faster workflow thanks to all of the keyboard shortcuts. I can plow through an inbox of 30-40 items in 10 minutes or less. The key to OF is you have to really think through your system's arrangement. It's biggest weakness is the inability to put something in multiple contexts (todo has tags, I think, which allows this).
Also, the perspectives makes OF very good at showing you exactly what you want to see when trying to actually get stuff done. In todo, it's much harder to only see the items you want. Todo's lack of start dates was the deal breaker for me, as I have projects different points throughout the year, and I don't always want to see them until I need to.
Check out David Spark's intro to omnifocus videos: http://www.macsparky.com/omnifocus-screencasts/
Referrals for your consideration:
Dropbox: https://www.dropbox.com/referrals/NTE1N … src=global