When comparing BusyCal vs Fantastical 3, the Slant community recommends BusyCal for most people. In the question“What are the best calendar apps for Mac OS X?” BusyCal is ranked 1st while Fantastical 3 is ranked 16th. The most important reason people chose BusyCal is:
Alarms may displayed in the BusyCal Alarm Window or the Notification Center. Snooze alarms for any duration, including x minutes before start, Set default alarm intervals for new Events, To Dos, All-Day Events, and Birthdays & Anniversaries.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Custom Alarms and Snoozes
Alarms may displayed in the BusyCal Alarm Window or the Notification Center. Snooze alarms for any duration, including x minutes before start, Set default alarm intervals for new Events, To Dos, All-Day Events, and Birthdays & Anniversaries.
Pro Latteral bar
Pro Weather, moon-phases and graphics
Display a live 10-day weather forecast and moon phases. Drag-n-drop images into your calendar with the Graphics palette. Customize event fonts, sizes, styles and colors.
Pro Custom number of days/weeks
You can customize the number of weeks shown per month, or days shown per week
Pro Great support and development team
Pro Smart Filters
Create Smart Filters to display Calendar Sets, a custom view, or events that match a certain criteria with a single click.
Pro Integrated To Dos
To Dos can be displayed directly in your calendar and carry-forward until completed. To Dos in BusyCal are compatible and sync with the Reminders app on OS X and iOS.
Pro Snappy and light on resources.
Pro Sync with OwnCloud and others
Connections are more stable than in Calendar.
Pro Amazing usabiliy
It has a neat design and gives a great overview on events of a day. Adding and removing events is easy.
Pro Joining Conferences via context menu or hyperlink in event on calendar
You are late and you have to join a call, you want to be fast.
Pro Integration of Google Meets when creating events
Cons
Con Expensive
Con No MS Teams Meeting Integration
Con Displays parallel tasks strictly without overlap
This can lead to not being able to read text in Week view.
Con OSX and iOS Only
Keeps you tied into the Apple ecosystem, not that it's a con, just an observation.
Con Doesn't have a widget
Doesn't contain a widget for the Today section in the Mac Notification section.
Con Doesn't support sync of event colors from a Google calendar
Con Online sync only
Con Yearly subscription
Even though you might also use cardhop, subscription based models are unpopular.