Minimal looks and is clearly integrated with a lot of useful tools. That makes me more productive than ever. The most thing that I liked of Things is the one minute setup and you can use in every moment of your day.

Things app comes with a beautiful clean UI and simple philosophy on how to organise your tasks. Just put anything that pops up into your head (even when on the go) into the Inbox and review later. Promised to do something but not sure when - put into Someday. Things will show you what you planned for today, what you have for upcoming days. Not a simple (one-step task)? - Take advantage of a Project setup. Things proves that it shouldn't be complicated (as long as you won't complicate it too much)

Easy to use, fast task capture, great interface.