But Core Data is difficult to use properly in a multi-threaded application, and Realm suffers from the same uneasy crossing of thread boundaries. Both generally lack a single source of truth. And who likes those pesky changes notifications that come at the wrong time?
“Graphics are not merely cosmetic. When they are clear and consistent, they contribute greatly to ease of learning, communication, and understanding. The success of graphic design is measured in terms of the user’s satisfaction and success in understanding the interface.” pg. 9