I installed it on my Sempron machine; I used the x86_64 version. The LiveCD worked without problems, the installation was uneventful. After rebooting into the install, I tried my usual tests of using Youtube (or Pandora), playing a DVD and playing an MP3.
Going to the Youtube site in Firefox gave me an info bar at the top of the screen about missing plug-ins. It gave me the option of installing Adobe’s Flash or GNU SWF player. I chose the former, expecting it to crap out because of the arch difference, but the dialog downloaded the 32-bit compatibility libs and flashplugin-nonfree and after a Firefox restart youtube videos worked just fine! I watched the latest Flyers highlights and cheered on our man Briere! Score one for Ubuntu!
Then I put in a DVD. Totem asked me to install some additional codecs, so I did, but then it gave me an error “unable to read stream”. I surfed over to the help pages and installed libdvdcss2 (and w32codecs while I’m at it) from Medibuntu. This step is still non-trivial for a regular person, I think, although they merely have to copy a few commands from the instructions: https://help.ubuntu.com/community/Medibuntu
Then I put the DVD in again. Totem asked me to install some additional codecs again, so I complied. Then the DVD played. Awesome. Full-screening worked, and there is no longer the stuttering of the previous releases. Also, the video works with the “desktop effects” that are turned on by default, which didn’t work in Feisty (at least on my hardware). Things are coming along.
The RestrictedFormats page suggests also installing w64codecs on x86_64, so I did. Then I surfed over to somafm.com to try an mp3 stream. Rhythmbox opened and played. Excellent!