Great post, very interesting. I am not a seasoned engineer like the OP but I do like my Python and without having to learn the hard way, I have the same conclusions laid out here. It's easy to get excited (I'm very interested in Erlang myself), but there's a lot of practical matters.

I was left wondering, it was noted that 3 servers are used and another language may only utilize 1. If Python was used, you could use PyPy and possibly keep a "commodity language" like Ruby but get to keep it possibly with the performance boost. I use PyPy for everything.