This app has helped me considerably with time management between school, work, volunteer activities, and my personal life. Besides calendar integration and the iPhone widget, I have enjoyed having a scheduled day planning session that forces me to look at each task and make an active decision about when I want to complete something. This helps me keep tasks from "slipping through the cracks."
I started using the app after I sustained a traumatic head injury years ago and was experiencing serious cognitive deficits that were interfering with my life. I couldn't even remember to go to work in the morning, but this app helped me hold down a management job while I recovered.