Edit: looks like the inefficient is due to overclocking. An antminer is 1w/gh at 80gh.
but that would involve more chips to achieve 180GH, costs are kept down by clocking the chips to the max performance.
Yea but the fact is they can achieve the same gh/w ratio on 55nm chips. Bitmain can always keep lowering the price but they wont be able to compete with knc 20nm or asicminer 40nm. Unfortunately neither will BA.
But we have a long time before efficiency plays a critical role so it might be better to go with a cheap miner like Blackarrow/Bitmine rather than an efficient one.