[corresation]

but the ability to swap out circuit boards on a SteamMachine is appealing

The plug-and-play thing has never really worked. However not having to wait the normal generational time between consoles would be an advantage -- it was always baffling that each iteration of the 360 and PS3 (there were many of each) couldn't improve it in some way beyond making it smaller or lower power. GTA IV on the 360 had draw distance issues and would stutter mid-town -- it would have been nice if some GPU improvements in the 2nd and then 3rd edition eliminated that, etc, but the nature of that platform makes it so they can't.