I looked up the specs on the new 3,000 GH/s Neptune from KncMiner and thought that it would make a great purchase. But when you try to work out the ROI, the numbers don't work unless BTC gets somewhere close to $2,000, you get the unit next week or you have solar panels.
$2,000 is possible, but that's a real speculative play given the $1,200 to $750 fall in the past few days.
http://mining.thegenesisblock.com/a/c7d1b8bf04
Which is the way to go?
Might make sense to also see whether you profit more than if you had just bought BTC and sat on them. It would be hard not to ROI if BTC spikes enough while you are holding your mined BTC and machinery instead of the amount of Bitcoin you could have originally bought with the same amount of money.