All great questions. If you are looking for long term stability of a neighborhood, schools tend to be the best predictor. Campbell, if the address is within the Moreland school district have excellent elementary schools but may not have the best middle and high schools compared to Cambrian. In particular, the 95117 (West San Jose) and 95008 zip codes have homes in the Moreland school district.
Cambrian schools that are within the Union school district have some variations but are the most solid in regards to K-12. Carlton, Oster, Guadaloupe, etc are all good elementary schools. Dartmouth for middle and Leigh High School. You can down load district maps and get a better feel. In general the zip code is 95124 but also some are in 95118.
Willow Glen offers one of the best communities and is most convenient to Silicon Valley central. However, only the Booksin elementary school is high scoring. The middle school and high school are significantly lower than any of the Union School districts. http://www.unionsd.k12.ca.us/
(look toward bottom of page for map.)
I agree with Patrick that buying a home should be a complete decision in regards to lifestyle, commute, community, and schools. Also recognize that a "zip code" does not guarantee a placement in the desired school. Due to the popularity of some schools, re-distribution of students to other schools can occur. It is always best to check with the school and or school board before making a decision.
A great resource for looking at all grades on a map - http://www.schoolperformancemaps.com