Macworld:
The best iOS calendars in the field don’t just look great, they offer their own unique concepts, distinguishing themselves by how they handle and present our data. Whether it’s event input, intelligence, social integration, or notifications, calendar app makers have added a wealth of features and functionality to the stock iOS calendar, to the point where Apple has even begun to borrow popular features just to keep up.
My life isn’t busy enough to need a powerful calendar app but I have used and liked Fantastical in the past.
I love Fantastical on the Mac and on the iPhone (including the great Watch app)… Not perfectly happy with the iPad version though. While it works perfectly fine, the lack of alternate views (like at least a month view) feels wrong, especially on a device as big as the 12.9″ Pro.
… and since they have added a slew of great Exchange features to the desktop app, I look for them in the mobile apps almost every single time (yeah, my bad, I know).
The Apple calendar app works perfectly fine.