Thread programming is hard. A lot of people point out different ways of doing it and say "if you're not a terrible programmer, threads work fine", which is all well and good, but they are still much more error prone than async and process models. This is one of the reasons Apple wrote GCD, which is a very interesting approach to threading that makes the messy parts of dealing with threads easier.

I would agree with the author. Unless you have a compelling reason to use threads, processes and async tend to make for more correct programs. However, they're often more difficult to get started with. Trade-offs, it's what we do :).