A new beta of SteamOS is now available with some nice additions and fixes. First up is that those with computers that don't have a UEFI BIOS, you can now give SteamOS a try as that prerequisite for installing the operating system has been removed.
Another feature that might get some more folks interested in testing the new version out is the option to do a duel boot and custom partition in the Expert settings. I know I'd be more apt to try it if I could still get into my Windows 8.1 install and not have to make it and all or none prospect when installing SteamOS.
Be warned though the features have very little testing behind them so it still might blow up your machine and SteamOS still isn't ready for mass consumption yet. If you feel a little adventurous though, why not give it a try.