I would be happy to give you as many details on Portola Valley as you'd like. I live in Ladera, which is unincorporated San Mateo County with PV address and I am very familiar with all of the areas. I don't think the answer below is especially accurate - or at least it is overly generalized.
To answer your question thorougly would take pages of text. Give me a call if you want. I will NOT try to make you a client of mine or follow up with nag emails or phone calls. You'll just get the facts.
And yes, I am a real estate agent.