(In which I subtly brag about being able to beta test the iPad version of OmniOutliner.)
Watching a program develop from its early stages is a neat process. When working with a nicely designed program, it's easy to forget that it went through many developmental steps to get there. Once a program exists, it feels like, "Of course! Why wouldn't it exist?" Look at the word processor for instance. It's fairly commonplace nowadays, but at one time, we just used typewriters.
For anyone interested in creating an outline, or using outlines with templates in mind, OmniOutliner is a very slick program.