Fantastical is just an excellent calendar app. The integration with Reminders is great. Did I mention that natural language input is brilliant?! I can work with multiple Exchange, Google, iCloud calendars, designating events, reminders, frequency, times, recurrence, alerts and notes all with a simple sentence or two and without every pulling my hands from the keyboard. That includes launching the app and entering multiple events and reminders. This app has completely changed my workflow for the better and has allowed me to be far more organized than I could ever seem to be with the default OS X Reminders and Calendar apps.
If you think it’s insane to pay $50 for a calendar app, you’re wrong. At least, if you demand more from your calendar than what OS X Calendar provides.
There is a little bit of a learning curve, but it’s minimal and the responsiveness of their support staff and the thoroughness of their support documentation has really impressed me.
GraceBorn about Fantastical - Calendar, v2.2.5