Greenbrae and Kentfield share the same great school district, however, Greenbrae's average price for a single family home is: $1,120,000 where as in Kentfield the average is $2.229,863. (Condominiums are not calculated in the average price of a home.)
Kentfield does have larger estate like homes which drives the average cost of a home up. Greenbrae homes are more modest and as a result highly desirable. Both share the same ammenities as far as shopping, but Greenbrae is closer to the freeway.
Weather wise, Kentfield has slightly more extreme weather, meaning it is hotter then Greenbrae in the summer and recieves more rain in the winter. Greenbrae is closer to the water and recieves more of a breeze in the summer
Bottom line: Both are wonderful places to live you can not go wrong in either areas. It just really depends on your budget! Greenbrae, you get more bang for your buck housewise. The location of Kentfield, is further away from the freeway and homes tend to be bigger and are in a more natural setting. Keep in mind what I am saying is a very broad generalization!
i hope that helps!