One of the things the author failed to mention, when he asks if Erlang is difficult, is it's verbosity for anything non-trivial. Just try building something using WebMachine for example. You will end up repeating the same tedious boiler plate code for each and every resource.
Very, very, fortunately the Elixir project seems to be making some headway and may just bring some decent language usability to Erlang. Erlang, is great architecturally, but in a lot of ways it's a toy language. It is going to need to evolve a bit to become palatable to the mass web development market.
I don't know much Python but as far as I k now it is capable of extension via mixins and Java can do similarly through AoP and inheritance. Erlang can do neither of these out of the box.
What I'm really referring to is how dry a set of modules is capable of being, avoiding repeated boiler plate code being employed each and every time.
Very, very, fortunately the Elixir project seems to be making some headway and may just bring some decent language usability to Erlang. Erlang, is great architecturally, but in a lot of ways it's a toy language. It is going to need to evolve a bit to become palatable to the mass web development market.