This discussion focused around the possibility that the units do not meet the safety standards required for consumer products/use, only commercial... see?
So in the original BabyJet announcement they were pretty clear that the equipment was only intended for use in commercial environments:
HashFast’s Golden Nonce (GN) is a 28nm ASIC chip that performs 400 Ghash/s at nominal clock speed and consumes less than 0.65 W/GH. It can be underclocked for greater efficiency and overclocked for greater performance. The chip has on-die thermal controls to allow operation at its absolute maximum performance. This equipment is solely intended for use in commercial environments.
Otoh, according to John the Sierra is the Commercial grade product while the BabyJet is the Consumer grade product. See:
http://www.youtube.com/watch?v=5yj-mmnRWYc&t=56sSo as usual with HF, a is b, left is right, BTC is USD, in stock is out of stock, exact dates are anticipated dates, guaranteed dates are intended dates, shipping is not shipping, good news is bad new, October is November, November is December, December is January, 2013 is 2014. you get the drift.