Anyone using it? I've read about it, but is there an advatage to using it? or not using it?

I'm not using it. In the future, when I have more than 2 servers for network logon I might set it up.

When you have two Terminal server 2008 application mode you must enable Terminal Service Session brocker for Load Balancing between them.

when a client connect to the session brocker server it make decision to send this request to the less connected users.

I am using it and it is great.