How does the community determine which exchanges to trust? It seems there is little legal recourse if an exchange runs off with your cash deposits or your bitcoins.

I am having trouble at the moment with Intersango - a deposit I made has not been credited, and their support department seem to communicate only once every 3 days. I can't tell if this is a scam that they pull on newbies, or if they just have poor customer service.

Is there any trusted review site for the various exchanges out there, or a place to log complaints?