Current recommended approach to "chat room"-type app?

Hi,

I've been googling around looking for a good approach to doing live
updates of my webpage. I've got a fairly extensive application
already, using traditional rails, and I'd like to have a page update
in real-time, hopefully without having to completely rewrite the app.

One of the most promising approaches looks like Faye, but the
railscast I saw was from 10 months ago, which seems pretty old for
this technology. http://railscasts.com/episodes/316-private-pub

"Rails 4 Live Streaming" looks promising, but I'm not sure, and since
this is a released product, I'd like to only use an officially
released version of Rails.

So, what are you using to do live updates? What are you looking into
for live update? What problems have you run into? Will Rails 4 solve
all our problems?

Thanks! ...and sorry for the broad topic.