I installed a Roku XD yesterday to avoid having to take my notebook to the larger external monitor whenever I wanted to stream sermon video for more than one person to see. My initial experience is quite positive. I had only one problem in getting started, but it was significant, so I will mention it and the solution.
Initially, I could not get video from SermonAudio, only audio. Each time that I tried to start a video (either stored video or live webcast), the Roku switched to a "Retrieving" screen but then after about 30 seconds apparently timed out and jumped back to the prior screen. Ultimately, we determined that this was a firewall issue, not a Roku issue. When starting SermonAudio webcasts in Firefox, I have been having to use the "Alternate Stream" because of the firewall in my DSL modem. The Roku provides no way to choose this alternative (not that I found, at least). I solved the problem by opening port 1935 to TCP traffic, thus enabling the RTMP protocol that SermonAudio uses. Not only did this enable SermonAudio video through the Roku, I no longer need to choose Alternate Stream on my PC. Hope this helps others.