The ease in which you can share files with multiple people at once. It's easy to create different versions so that everyone can work on their part independently without having access to all other parts! I dislike how difficult it is to find someone who has used the program before - when searching online there are plenty of articles but they often don't provide any insight into what went wrong or right about Teamwork. If anyone wants an easy way to manage project management then this is your tool. Easy file sharing makes communication between team members much easier than emailing documents separately.