[papa]

This site provides some good neighborhood-specific price/square foot info.

http://pricesquares.com/#/county/1/san-francisco/

You can see that the north and northeast portions of the city carry the highest rates (close to $1k/sq foot in Pac Heights and the Marina).

Zoom in to drill down to smaller neighborhoods/sub-districts.

For comps between SF and Palo Alto, I'd recommend Redfin. Last I checked, the Palo Alto prices were above SF prices (on a square foot basis).

Edit: I'll just add some more detail!

Here's the Redfin report for Palo Alto ($1,168/sq ft): http://www.redfin.com/city/14325/CA/Palo-Alto

Here's the Redfin report for SF ($660/sq ft) http://www.redfin.com/city/17151/CA/San-Francisco