I would not suggest investing. Just put full hash power until you get to level 2. It is exponential :)
Once level 2 put the hash on a lower level and add doge mining. Then check your withdrawals. In any case always check monitoring website before even signing up to a service like this.
I could give you couple more sites like this but not for investing. Just to use their free hash power or whatever they offer and forgeting about it for a while. Month or so. If they still exist later and pay - that is good.