Fantastical 2 has been my calendar app of choice for the past few months. My one quibble so far has been that it was only designed for iPhone. I have used it on my iPad in 2x mode, but it has never been a great experience.
That all changed with today's release of Fantastical 2 for iPad. All of Fantastical's key features—including the DayTicker and its ability to understand natural language input—have been carried over from the iPhone version. The main difference is that the iPad app takes full advantage of the larger screen to display more information at once. It's more than a basic calendar; it's a detailed dashboard for my schedule.
As it stands now, the iPhone version is where I will quickly create new events, and the iPad version is what I'll use to manage and review existing events. I recommend picking up both if you haven't already done so, especially since the iPad app is on sale for $10, a discount of 33%.