I switched my homepage to Workflowy when I saw it first here on HN and it has been a great boost to my productivity since. Maybe nothing specific to Workflowy itself, but just the fact of having a todo list as homepage.
Even though I didn't keep up with updating the HTML to represent what I was working on, I became much more aware of my actions and their relations to my responsibilities since then.
I found it to be a valuable lesson.