I'm in the process of acquiring a Rockminer R-BOX as well, but I am curious:

Why are people who already own S1 units buying R-BOXs?

They seem like great little units (I ordered one, and it will be my first real miner!), and they run at low power, but based on the calculations I've done, they seem to be nowhere near the bang for the buck or ROI of an S1.

Just curious why you big/bigger-hitters are buying em as well.