RichFaces mediaOutput component, as you can see in live demo, can be useful for displaying various media content you generate, as said on the linked page, "on the fly". Sure, it worked quite well in the demo, but once we started using it in our application, it turned out to be quite a burden.
I noticed something was wrong when I tested it in Internet Explorer. The damn browser still holds quite a bit of a market, although competition is numerous and, in my opinion, better. Firefox is my default browser for about five years, and I am satisfied with it, although since my recent purchase of a Macbook, Safari became my primary browser (I simply like the cover flow stuff) although Firefox is still used from time to time and is a default system browser (mostly for my home projects). But using Firefox in a corporate environment is still novelty new in my country, and some companies simply have company standards which require MS technologies, including IE (even in version 6.0!). So, you simply can't avoid browser compatibility.
We have lost quite a lot of time and finally implemented our functionality using simple HTML OBJECT. Works everywhere. In fact, RichFaces eventually transforms your mediaOutput component into OBJECT so the result is the same, only RichFaces gets sometimes lost in the way.
I still recommend RichFaces for JSF frameworks. It is good, nice looking, but it is nice to know it's limitations. But the only way to get to that is by painful experience. But that is our job. My motto, which is popular children song sang during kids games, describes our programming work: "Kolariću, paniću, pletemo se samiću, sami sebe zaplićemo, sami sebe rasplićemo...". The bold part, in Serbian, says:"we tangle ourselves, we untangle ourselves". I think you get it :)
As for ADF, well, it has taken a few years of my life, been a good experience... I wonder if I will be using it again. It is browser-safe, obviously well tested, pricey, and, taken in account ADF bindings and data controls, good only if you have well defined and stable architecture underneath (yeah, business components).