iOS 10 is chock full of little enhancements that make it a really great release for customers and developers alike. For recaps on what's new (and how to take advantage), I recommend two resources:

The iOS Mac Stories review

Federico and friends have out done themselves once again. This is a great way to learn about iOS 10 in depth.

iOS 10: A Take Control Crash Course

Josh Centers from Tidbits has put together an excellent resource on how to quickly take advantage of the new features in iOS 10. You can purchase it for $15.