The winner in the mining game is the one who as the most power efficient machine (or the one with free electricity).
I know Neptune's will be hashing while Antminer's will be turned off because they use to much electricity.
At the current prices of mining hardware the difference betwen a antminer and expected neptune effiency matters very little in the grand scheme of things when calculating ROI. Lets imagine that neptune hits 0,5GH/w and compare that to the antminers 2W/GH.
per TH/s of Neptune/Antminer we get the following at 0,15 usd/kwh
Neptune 0,5x24x30x0.15 = 54
Antminer then = 4x54 =216
So the day you have to turn off your antminers, on that day your neptune will make 162 usd/month per TH/s. While most are expecting KNC to over deliver the only promise they have given is 3TH so that would make it roughly 450 usd/month. Doesn't look that terrible but diff will not stop increasing the day the antminers are turned off. All I'm trying to say is that at current prices getting the right price/gh for the delivery window is more important than power consumption, at least while we are no longer talking of order of magnitude differences between offerings anymore.