I use it all the time, really easy once you are used to it. Mine is embedded in Outlook/Chrome/IE and I can start one with a click of a button.
Also has personal rooms now - which is much better.
As someone above pointed out - you can pay per use. I have a corporate login.
Cisco WebEx?
Not sure. We're a business partner or something, and we use it for doing teleconferences with clients and whatnot. Really an amazing system.