From what I've seen, they all look identical on the outside, the only difference you'll notice are the ports on the full node vs. the others, you won't have HDMI, etc. Not sure on the open source firmware, I don't think it's been open sourced yet. If it had been, there'd probably be links on the main futurebit site.
Oh nice, thanks! That's great, I was almost expecting to get a bare hashboard with a micro USB connector.
Riiight, makes sense as well. Maybe I'll get just a Compac F first. I'll see...