An S-Corp is actually worse from the VC standpoint than an LLC, b/c S-Corps don't require incorporation (DBA's can apply for and receive S-Corp status). This means it's easier to take the money and run.

Some VCs prefer LLCs because it gives them the risk-minimizing benefits of a corporation, while at the same time giving them a hand in managing the business (a la partnership form). HOWEVER, many VCs, especially the smaller ones, are unfamiliar with LLC law, and avoid it b/c they don't know about it. Some VCs prefer S-Corp because it ideally gives them access to the founders' personal assets, but in practice, a bankruptcy court will try very hard to deny this benefit.