[Beltiras]

Interesting project. I've up till now used Twisted or Tornado (actually swampdragon.net). My choice would be dependent on scalability and performance.

[slact]

I consider those two and socket.io my main competition. Nchan is built to scale, but of course you'd need some numbers to back that up. I plan on doing benchmarks once I iron out the documentation, although I realize it would be a great selling point to have the numbers ready right away.