Raspberry Pi interview: Eben Upton reveals all (Linux User)

In the system to system price, I included the same $15 - $20 adder. Actually, I computed a $20 adder for the BB system vs. $15 for the RPi. If I correct the math, it's pretty much exactly 2 to 1: $90 => $110 vs. $35 => $55.

And sure, you may have a spare keyboard or USB power adaptor around (many tinkerers will), and that makes a difference when you're buying one or two to tinker with. My point is that you can't really count on that if you're, say, outfitting a classroom or doing some other mass deployment.

That brings me back to the final point I was trying to make: Tease apart the different scenarios where you might be choosing between these, and see how the strengths and weaknesses of each play into those scenarios. Reading through these threads, I see a bunch of goalpost shifting, because different commentators are assuming different use scenarios.