Being very proficient in Erlang and able to bumble about pretty effectively in Haskell, I can confidently say that while the two languages require complementary

Being very proficient in Erlang and able to bumble about pretty effectively in Haskell, I can confidently say that while the two languages require complementary skills they target two different problem domains: Erlang's a heavy-lift rocket, Haskell's a sub-orbital rocket-plane. Well worth being at least familiar with both.