>If I have to spend 2 months searching for a replacement for an Erlang developer that quit, well, that's not good at all. First of all, by requiring Erlang you

>If I have to spend 2 months searching for a replacement for an Erlang developer that quit, well, that's not good at all. First of all, by requiring Erlang you will get mostly "above average" programmers. Second, your "senior Python guy" will still nede time to get into the problem domain, from a week to half a year. And third, any sufficiently capable programmer can peek Erlang to his own productivity level in two weeks. If he has previous history of functional programming - one week. Again, functional programming indicate "above average" programmer, even plain interest matters.. So you're better with Erlang than Python. I know, I was. ;) I think that your "senior Erlang" friend just loves to change companies or have talent for it.