The most legit, if not the only legit cloud mining is offered by Hashnest.
Hashnest is a Bitmain company that throughout the years has been producing the most powerful and efficient ASIC miners. Currently they sell the AntS9 (SHA256 miner), AntL3+ (scrypt miner), and AntS3 (X11 miner). AntT9 coming soon.
The reasons they have been able to stay legit in cloud mining:
1) Hashnest produces their own famous Antmain ASICs. Do not buy mining rigs from "middlemen"
2) They are based in China where electricity is sooooooo cheap. Therefore low maintenance fees (I believe if you are located in an expensive energy country like I am right now, physical home mining would be less profitable than Hashnest.
3) Their mining pool has about 20% of the global BTC hashrate.
4) Unfortunately i think they are trying to centralize or control bcash, so no room for any scams or they will fail in centralizing it.
5) They also have hash market. Where people could trade their hashes for BTC
6) If an ASIC becomes unprofitable, they give you the option to have it shipped to you (since it belongs to you), but you would have to pay shipping and handling fees.
7) Recently they created some lottery system where u can buy tickets with Bitcoin to win a miner like S9
They also have the PACMIC contracts which are very low risk, but low yield (currently not offered because of the stupid forks)
9) They keep trying to reduce electric cost and making making announcements about it. Right now I believe is about $0.07 per KWhr. I remember it used to be $0.09 like 2 years ago and at some point they announced it up to $0.11 temporarily due to some disagreement with their power supplier, until they changed it as brought it back to $0.09
10) There is no HashNest referral program! (Usually associated with scams, ponzis, pyramid schemes HYIPs, ... etc.)
NOTE: passive mining at Hashnest is only profitable if you buy a whole miner from them (at lower cost per GH than the markateplace). You could make extra profit by buying low and selling high, but you won't make any ROI if you just buy hash shares from the market.
That said, although I already made ROI on 2 S7 miners in about a year (S7 still profitable on hashnest), I have been desperately trying to by an S9 miner since March. I was too late to the party when they released S9 contracts and there hasn't been any announcements of any further S9 batches. They are in huge demand and tough to grab. My only advice is to try to check daily for announcements and the Hashnest store for when a new batch becomes available for cloudmining. They used to release like 3-4 batches a year, but the more time passes the less batches they are releasing, which makes some sense. Usually mining operations need capital in the beginning, the more they grow their mining operation, the less capital they need from investors to produce more ASICS for their personal use.
Now my turn to ask!
Does anyone have any insight or experience with NiceHash? I've been trying to figure them out but there's too many variables. I'm finding it hard to believe that NiceHash is profitable since there are 2 middlemen: the hashrate renter and NiceHash. Also, if someone has a mining rig with cheap maintenance, Why on earth would he rent it out rather than making all the mining profit himself?