We live in a Boston suburb, where our three children attend public school. Sorry, but what little I have heard about Cambridge public schools has not been favorable. It's my impression that many parents who work in Cambridge but have the means to send their children elsewhere often do so, either by sending their children to private school or buying a home elsewhere. Within Boston, Brookline has a good reputation.
If you joined the MA Gifted mailing list
https://groups.yahoo.com/neo/groups/MAGifted/info and asked your question there, you would probably get some replies.
