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.
If you think about it, while a faster time to market obviously benefits the pre-order customers, a higher power efficiency benefits KNC because they will be able to sell the 20nm ASIC chip much longer. Regardless, I've actually decided to keep my order because I'm going to gamble that the early "customer appreciation" batch will at the very least break even in BTC because I believe they do plan on rewarding their customers in whatever their actual schedule is which I will bet is early April. I just hope they can pull it off...