i think hashnest is best of the best! i`m buyer miner from that company. i`m trust him.
aplenty cloud mining ponzi, but there are some as well which I think cloudmining site who real minning, like hashnet
but I want to ask, how long it takes for ROI in hashnet ?
if you mining in hashnest, I suggest for now you can stick with S5, since they running luckyhash program for S7 until February, that's make S7 price unstable since people getting free GHS there and selling at cheap price.
For S5 if my calculation is correct, can be ROI within 5-6 month, provided you also get profit from trading GHS (so not pure mining)