Many people believe cloud mining is a scam. In fact some cloud mining websites have been known to be scams in the past. There are a few legit cloud mining website that are proven not to be scams however. These sites are genesis mining and hashing 24.
Most people are not aware that cloud mining is actually not a scam, however for most people its not very profitable. The main reason for this is because the difficulty goes up with the price, causing you to mine less coin per day, taking longer to get a return on your investment. Some cloud mining sites require a daily maintenance fee, these fees are very small but if they are not paid the contract will be ended. Also another thing to note some contracts claim to be lifetime contracts but in fine print they say the contract will be ended if its "no longer profitable."
So when your using a mining calculator and adding numbers up this all seems like a totally great deal in the long term but in reality the people that make the most money mining are the people with Youtube or lots of followers. Why you ask? Well the referral codes of course. These codes greatly help the person referring others and only help the person using the code just a little bit. A lot of Youtubers claim cloud mining is very profitable but they neglect to tell you that they make more money in referrals. Another way to become successful cloud mining is out of your control. You want the coins you mine to have lower value when you mine them so later on when they go up in price you can profit much more from them. But if you spent a year mining a coin and then the value goes down a lot. Now it will take you even longer to get a return on investment.
Here is a really good site that tells you the coins that are most profitable to mine at this current time. The site is called whattomine.com. This site is mostly used for regular mining yourself using your own rig or asic set up but its still usable for cloud mining and is a very interesting website. So although some people do well in cloud mining make sure you do your research first. Just because you don't have to pay electricity in cloud mining doesn't mean its profitable. Best to just buy low and hodl guys