@Iggy.
I think the major difference to the users of Linux and *BSDs simply comes down to driver support and manufacturer support. They both used to be in the same boat, but besides nVidia, I don't know any hardware manufacturers that directly release drivers for the various BSDs. I don't do much 'real time' processing myself, so haven't really played with the rt kernels myself. But you could always try adding your talents to it.. you know the whole open source thing.
I do tend to think that some Linux vs BSD vs Unix things are simply "well, they do it this way, let's do it just a bit differently" like device files. Also in my testing of various things, I've even noticed that arguments between common commands are different, like tail on a GNU/Linux system is different than on Solaris.
But really, where else would / could SteamOS go from Windows? It couldn't go to Mac OS, because they are going the same way Microsoft is trying to, having a "Only us!" 'app store'. Linux gives them the driver support, the ability to put whatever software they want into it, and the ability to distribute it everywhere. BSD gives them all that, just not the driver support.
All this talk about BSDs though makes me want to give it another shot. Been awhile since I played around with it.
slaapliedje