Calendar (Calendar.com) is a productivity tool from the company of the same name headquartered in Draper that helps users solve calendar problems by helping to save time, be more productive, and focus on the things that matter most.
I believe Calendar is the de-facto standard for scheduling and meeting these days. If you want to use it in an enterprise environment, it has a cost per user so I consider it to be a professional tool. If you have a very small business or personal matters, Calendar outside of Workspace is a better option, although it's almost the same tool.
Fantastical is excellent for someone who appreciates the ease of data entry without having to tick boxes and use drop-down menus. Fantastical also provides a number of different view options based on how the user prefers to see their calendar and tasks.
Better User interface. Everything you need to manage your appointments is here, on a site with modern design and full support for collaboration. You can also connect Calendar to your other favorite apps. For both personal as well as professional
Fantastical provides a visual experience that I appreciate more than the simplified Apple iCal design. It also provides a lot of options that help with the more detailed events.