What is the difference between the Free and the Premium Plan?
The main advantage of the Premium plan is, that you can add more than 5 users to your workspace.
Additionally, in the Premium plan you have access to the Annual View, which lets you zoom out your timeline to see the whole year. You also have access to Custom Colors, which allows you to customize your timeline and workspace even more.
There is also a bigger file size limit for the single attachment in task popup - 100MB (instead of 10MB in the Free plan).