Maybe check here also before you invest: https://bitcointalk.org/index.php?topic=173316.msg5632280#msg5632280

You can check the difficulty here on this page: http://bitcoinwisdom.com/bitcoin/difficulty
mobodicks 20% rise per month is rather conservative. It's actually closer to 20% two to three times per month instead of just once.

Currently the Gold contract will cost around 6BTC and I'm afraid it will mine not even half that amount during the contract period. So far cloudhashing has yet to come up with a decent reply on these concerns about the growing difficulty.