None of them I prefer to use, it's better to mine with hardware or real mining rig. Instead of investing to them, it's a good feeling if you can find it out that mining with your very own rig will give you a chill and you have an assurance that you are earning real bitcoin with the alt coins you mine. The contracts on those cloud mining aren't realistic, the life time contract on hashflare was gone so what do you expect? That's something untrustworthy.