mining sites currently very rare. Because many users who do not want to use this service. Most services will only end up on a scam. so it is better to use your money for something else, something more to make money of course.
Genesis Mining would be the best one among all. They could provide you a decent amount of bitcoins but It is entirely dependent on the amount of Hash power you invest into it. I could say that you can break through in an every year's time and profit from their onwards. They are offering a lifetime Bitcoin mining contract with your one-time spend on it.
