Pros and cons of node.js over ejabberd for chatwindow.com?

we are building a live video broadcast and group chat app which lets users share the live video over the url and be able to group chat with thousands of people clicking on that url.

We are currently using Flex NetGroups but doesn't work well with USB stick slow internet connection. The video comes in real time and text messages are delayed a lot to be really useful. So, planning to use a messaging system that works very well with low bandwidth connections and is scalable.

Two options we are considering are ejabbered and node.js - which one will be better and why?

Thank you Rajan Chandi