The actual user interface and the way to navigate around the app is very intuitive and easy to learn/use which would make me give it a high ranking, but the syncing issues drop down my rating because there are times where you add an item to the list and then it just disappears. Then when you add it again the sync will happen and now you have duplicates. The other negative with the usability is adding extra information to an item, such as files or comments or assignments. You can do it but it's difficult to tell which items have this information from the main screen. You have to click on them individually.