When comparing Calendar vs Fantastical, the Slant community recommends Calendar for most people. In the question“What are the best calendar apps for Mac OS X?” Calendar is ranked 2nd while Fantastical is ranked 12th.
Ranked in these QuestionsQuestion Ranking
Pro GNOME Native integration
It has online accounts integration.
Pro Currently in active development
GNOME Calendar is improved with every release cycle of GNOME.
Calendar for GNOME aims to find the perfect balance between features and usability.
Pro Supports multiple calendar platforms
If you're locked into using an Exchange account, Google Calendar won't work without 3rd party syncing options. Fantastical works flawlessly with Exchange and with Google Accounts so you can have both. It also supports iCloud, Office365, Yahoo, and Facebook calendars.
Pro Fantastical can comprehend natural language
You can copy and paste a line from a meeting note and Fantastical can copy down and present the relevant information
Pro Beautiful and highly polished design
Con No support yet for WebCal
No support yet for WebCal, such as those offered by Facebook events.
A workaround exists. Since this application uses the same background services as Evolution, installing it and adding the WebCal calendars there, also adds them to GNOME Calendar.
Con Poor interoperability with online calendars, does not connect to Fastmail
Con Only works on GNOME
Con Expensive for a single utility app
Fantastical on OS X costs $49.99 and an additional $4.99 if you want to use it on iOS.
Con Only supports iOS and OSX
Fantastical doesn't support web, Windows or Android.