On the 25th of August this year I decided to buy a little bit of hashpower (3 MH/s) for Ether mining on the well-known platform Genesis Mining. At this point in time I was still pretty new to the whole idea of cryptocurrency and was thinking I'd make more money this way. So I put in a small portion of my bitcoin at that point.
I've tried calculating the profitability of this contract since the day it started, but it has been hard due to a lot of different factors.
I put in 0.02 BTC, which at that time, was worth around $87 (based on a BTC price of $4.350). Since then the price of BTC has almost tripled, this changes my initial investment $234 if I just held on to the bitcoin.
During the first days of the contract it mined 0.00056090 ETH on average. Mind you Genesis doesn't pay out untill the total worth has accumulated up to 0.05 ETH. The difficulty soon went up and it only generated 0.0003 ETH per day. Then the difficulty changed again making me earn 0.0005 per day. During these past 3 months there are still a lot of days where I haven't earned a bit of ETH, these so-called "missing payments" have not been allocated yet and Genesis refuses to answer tickets from small-contract holders I guess.
At the same time the difficulty increased and decreased, the price of ETH was swinging like a monkey from a treebranch.
Yesterday I received my first payout making me around $23. If I can project these earnings for the next 21 months to come it will have earned me $180. I just changed the allocation of mining power to Ethereum Classic in the hopes of generating more money during the next few months. !
If I had just held on to that little bit of bitcoin I would've made a lot more... I guess this is my only advice to anyone considering a mining contract, don't do it. In the end you won't be enjoying the profit as much as the mining company will.