I think you can't talk about general criteria for web sites, just like you can't talk about general criteria for automobiles. Is a truck better than a family sedan? It depends on what you plan to do with it. You can say that a site that goes down almost every week is obviously bad, but what about Twitter during its first, shaky growing phase? Or to use a more common example, web copy brevity is usually good, but long sales letters convert well.
