I don't personally think that cloud mining is the best of the investments available out there at the moment. I mean, there's tons of opportunities out there waiting for you but you invest in a cloud mining site that has a 90% probability of being a ponzi? I don't see the need to take the risk for such small returns.

But if you really want to look into it I suggest avoiding ZeusHash and other dodgy websites at all costs, and I'm pretty sure that Genesis-Mining is a legitimate site.