iPhone: Checkmark 2 has long been our favourite alternative to Apple's Reminders. Today, it gets a couple of handy new features, including a Notification Center Widget and interactive notifications.
The big new feature here is the iOS 8 widget. From Notification Center you can see what tasks are due today. Likewise, you can now interact with notifications from the lock screen. Just swipe left to mark reminders as complete. Checkmark is on sale for $3.99 right now, which is much more affordable than it's regular $10.99 price tag.
Checkmark 2 [iTunes App Store]