The reason vlad sells contracts in the first place is because he knows that in four months the returns will be so tiny from mining and he would make more money from people purchasing contracts rather than he could make himself by mining.
His prices are also ridiculous. Last time I checked his monthly charge of ~400 euro is around $700USD, for ~1Gh/s/month. That's more than twice what it takes to build a machine capable of the same mining power yourself. At least going by the prices I saw in his post (I only looked at it today), the only people paying him must be those who haven't done the math themselves. And what does it say to you when someone goes around charging people for various things related to a fad instead of putting his money where his mouth is and mining for himself? I'm sure he's mining too, but he's making a killing by charging people crazy prices and then either pocketing the profit or putting it into his own hardware. Even if the market crashes he can sell the hardware and still make out really well. I can't say there's anything wrong with what he's doing, just not sure about the judgement of anyone sending him money.
NOTE: i'm basing that solely on the 400euro/month price i saw in his thread today. Maybe also everything costs more where he lives than where I live.