Ask HN: Suggestions for evented code

I need to write a lot of asynchronous/evented code for some complex chat purposes, so I am debating between 3 options:

1. Ruby with Event Machine

2. Javascript with Node.js

3. Erlang with/without OTP

I know/love Ruby the best, but am comfortable with Erlang or Javascript, so I'm willing to go with the best tool for the job - as long as it is one of those three ;).

As I see it the above options have the following aspects recommending them:

Event Machine

- Ruby is my favorite language

- Ruby community is awesome

- Ruby libraries are awesome too (though not sure which ones are good for "evented" environments)

Node.js

- The new hotness (for better or worse)

- Impossible to write in a non-evented manner - Peepcode screencast

- A lot of traction

Erlang

- Has many high-profile deployments (like Github and Ericsson) so it can definitely handle my demands

- Very robust language that has survived the test of time

- Hot-swappable code

- Scales well to multiple servers

- Pragmatic screencasts and good books

So for those who have used any of these technologies in production deployments (and especially if you have used more than one of them) I'd be interested in knowing about:

1. How did it scale (to many clients, across many servers) 2. How did you approach testing 3. How enjoyable/smooth/intuitive did you find the coding process 4. How much in-built support did you have for doing things "the right way"

FWIW I'm mostly leaning towards Erlang, but very willing to have my mind changed

Thanks! Nate