The best option for me by far because it integrates with my well established reminders and calendars in iOS so that I can continue using iCloud web interface, Siri and my existing shared lists and calendars with my family without having to migrate all my data into another app or platform. Its great and it serves as a much more reliable and useful interface than the iOS Reminders app. Well worth it.
activelifejs about GoodTask 2 - Reminders, To-do, Task Manager with Calendar