I've been having lots of fun with the newly released Fantastical 2 for iPhone. This calendar application got an iOS 7 redesign and it looks great. The new version now supports reminders and a much appreciated light theme, which fits in better with iOS 7. Flip your phone into landscape mode and you'll find a good looking week view.
Fantastical's premier feature has always been its parser. It is even better in the new version. You can type (or speak) in plain language and Fantastical creates an event. Now you can even create events with repeated formulas like the second Tuesday of the month. It now also can create reminders by starting sentences with "reminder", "todo", "task", or "remind me to.”
The new version supports Background App Refresh, Dynamic Type, and 64-bit support for the iPhone 5s. After a day of use, I've put it in my dock. The app is on sale for $2.99 but the price will go up to $4.99.