I tried Omnifocus and Things and decided on Things. Omnifocus is without doubt a fantastic productivity tool. I'm not knocking it.

But when it comes to productivity apps, I find it very important to get the UI out of the way so I can focus on the content. Things accomplishes this with so much grace that I can't help but focus on the tasks.

Omnifocus offers more options for organization, and when I switched, I missed some of the features, but I found I spent too much time managing my tasks rather than doing them. Still, it's worth looking at if you need an app to help you accomplish life.