Cloud mining will only be profitable if you have many referrals that also investing. For me, as a cloud miner, I do have some profits received from them but I cannot give an assurance if how long will they give profits to members as most of them or all of them rather will end up scam. For now I suggest you to use hashocean and genesis-mining and also invite more referrals to invest here. Happy earning my friend.
You cannot give a blanket statement like this. Some sites like hashnest difficulty, fees, ect are going to be the big factors on cloud mining you buy if you get profit. I would not get mining and referral games confused.
Sadly so many cloud mining sites are pure ponzi scams they need new people to buy in. They offer referrals so people come on sites like this and try to make a crappy scam sound good. If someone say's X site is the best cloud miner! Here use my referral normally they are not good source of info.
But seriously hashnest... or I would not touch the site right now. And still I'm more for buying hardware and having it hosted somewhere. Most in beginner forum are people with referral spam on cloud sites, they target this part of forum on purpose.