I live in nearby 95132, in a stronger high school neighborhood (near Hostetter/Piedmont) and when you go up into the hills the schools have higher test scores. However, the two elementaries in 95131 have decent test scores (if that is your measurement of choice) with Brooktree Elementary at 806 API and Vinci Park at 815. If you go up Hostetter to Piedmont, Ruskin API score was 903 last year, comparatively.
At http://www.GreatSchools.net you can compare schools by demographics, test scores, parent ratings, and more. Ruskin rates the highest of these (but that is 95132).
In 94086, Braly Elementary scored 828 last year, and Ponderosa 858. Ponderosa Elementary School is very highly regarded for its sense of community. It's in a great location near parks and the parent community is very active. Peterson Middle School is a great middle school! However, Wilcox High School has had some test score drops despite being a campus that feels pretty good from a kids' perspective. It is now not regarded crazy highly even though Santa Clara Unified works hard to have good results.
Sunnyvale property values are stronger than 95131, as far as weathering our current downturn. It is hard to say what will happen in the future. The demographics are also different, and you can find out more about that at http://www.greatschools.net.
The areas feel pretty different if you look at the community overall.
If you are open to 95132, the Ruskin/Sierramont/Piedmont Hills combo is great for schools and low crime. If you like 95131 for its easier commute and proximity to everything, you do give up some high school and property value quality. Yet my clients who like 95131 really like it for how easy it is to get things done.
Berryessa and Sunnyvale are very different in community climate. I live in Berryessa yet almost all of my listings the last two years have been in Sunnyvale (including a home I am selling now in 94087). So I see the differences almost daily!
I hope this helps!
Education specialist/mentor realtor