I can't speak to the specifics, but after working on a significant third-party SDK for iOS I can say that libdispatch isn't hard to use correctly, but it is eas

I can't speak to the specifics, but after working on a significant third-party SDK for iOS I can say that libdispatch isn't hard to use correctly, but it is easy to use incorrectly. Worse still, once you get yourself into a libdispatch mess it is hard to escape without a total rewrite.