People don't get what's a GH/S at CEX.IO : it is something that loose 50 % of its value every 15 days
As opposed to a $2.5k USD machine that never sees ROI and will have a HORRID resale value come, say, February?
1 GH/s at cex.io will also never see a positive ROI and will have a HORRID resale value in February, probably somewhere around 0.005 BTC, if you are lucky.