Chris has posted part 2 of his Extender review and he has a nice table of supported content which is always the first question when looking a media player devices.He also tested out the network performance.

When first setup I did have some pixilation and blocking while playing HD recordings and was prompted that I have a network issue.  I ran the Network Tuning Wizard on the on the Extender (which it prompted me to do) and it looked okay.  I rebooted the router and tried to connect again and was able to stream HD recordings without an issue.  I continued to connect over wireless for the remainder of my testing and didn’t have any other issues.

Linksys Extender Review Part 2: Extender Experience - Chris Lanier's Blog