Android was the surprise OS, with a decent playback of our HD movie. Unfortunately, playback stopped two minutes in and refused to go any further on the 256MB RPi. Amazingly, this occurred to the point whereby we had to re-image the SD card as Android refused to boot.
The 512MB version fared better, but the video stopped after 15 minutes. The video was viewable, although during camera panning there were cuts and tears, but we figured that to be the limits of the default state of the OS. MP3 playback was as good as you're going to get through the audio port, But the 256MB model was almost impossible to get running in anything resembling a decent media device.
Raspbian didn't have anything to play the movie or MP3s on by default, which is unfortunate as the inclusion of OMXplayer wouldn't break the bank in terms of size. We will grant you that one of the goals of the Raspberry Pi is the users' foray into the world of open source, Linux and so on, and that by learning to use the Terminal and software repositories the user gains a better understanding of the environment they are working in.
Risc OS didn't do much better - both the movie and the MP3 failed to load up, as it did on Plan 9. Although both Risc OS and Plan 9 can make very good media viewers, the default software isn't able to open the most common modern media - but with some tweaking, downloading and installing they can.
Arch is exactly the same. It boots into the Terminal, so there's little hope of getting anything graphical to work out of the box. Arch can be made into an amazing media box, but the learning curve needed may put off the inexperienced.
Raspbian - 4/5
Risc OS - 3/5
Plan 9 - 3/5
Android - 2/5
Arch - 2/5
Attitudes toward software
They may take our OSes, but they can't take our freedom!
All of the operating systems tested here have their source code available from either their respective home pages, or other sources relating to the OS itself; so in essence they are all free, and will most likely continue to be so unless - of course - things change, in which case the community would most likely be up in arms in a matter of seconds.
Risc OS for the Raspberry Pi is open source, version 5.19, and the code is maintained by a voluntary group; but the latest version of Risc OS 6 requires the user to sign up for the Select scheme at £99 per year, and is wholly proprietary software, with no public access to the Risc OS 6 source code.
Plan 9, Arch, Android and Raspbian, as we all know, are free to manipulate, install and develop on, as per the ethos of Linux as a whole, and the Raspberry Pi Foundation.
The overall attitudes to software freedom from the collective projects are one and the same, in many respects; the enhancement, further education and use of each of the projets is in accordance with the various regulatory thoughts and aspirations of the open source community, and those managing it.
It's a bit of a difficult test to grapple with, the verdict will see each score the full five stars, as each is free and the attitudes are those of freedom. It's unfair to label Risc OS as being lax in the open source arena because of the closed nature of Risc OS 6, as the community behind the open 5.19 for the RPi is willing and more than able to manage the free software aspect.
Raspbian - 5/5
Risc OS - 5/5
Plan 9 - 5/5
Android - 5/5
Arch - 5/5