Genesis Mining and Hashflare. For the price these company sells their contracts you can ROI in almost a year, without difficulty change and change of bitcoin exchange rate. Due to difficulty change it's much longer, so ROI is even more difficult to reach, if reached at all.
So for me ROI (under mentioned ideal circumstances) must be held in less then half a year, then -when real circumstances like difficulty changes are considered- ROI is reachable in less then a year.
You should read some of the statements from their real users. One guy bought a 2 year contract with GM and got it terminated by the company because they said it wasn't profitable anymore. That's how your ROI in a year works with these companies. You buy a lifetime contract and it suddenly ends after a year or 2, right when it could start being profitable for you.
That's why I never suggest to buy such contract directly.
I buy from people who are mostly disappointed in the contract, for a price I guess
I am reaching ROI in a year. And I do look to the contract (GM changed the prices for maintenance/electricity several times, so older contracts are even less attractive) before making my decision.
And I do not know how they will manage, but both GM and Hashflare's current lifetime contracts mention that the contract will be reinstated when it becomes profitable again.
At this time it's going well but I know that's no guarantee.
I also don't believe in cloud mining, I really think they are all just ponzis waiting to pop and run. It's quite easy to lie to the customers that they are really offering legit miners that they can mine on. Not to mention, they are just giving you a crap small amount of interests per day and it would not even beat inflation at the end of the year.
First: I agree that most "cloud miners" aren't mining at all (=ponzis), as mentioned before. However there are few real cloudminers - only even they are with little chance for profit and when you have profit it is a very small one.
What inflation? When you compare hodling and (cloud) mining, when you reached ROI every satoshi you earn more is profit.
When you buy 1 BTC after waiting it is still 1 BTC
When you buy cloud mining contracts and you reach ROI (Yes, little chance and/or after long waiting) and make a satoschi profit you have 1.00000001 BTC
But you are absolutely right that there are much better/faster/safer ways to earn more with that 1 BTC.