Two general notes:
- Most "good" schools in Spain "cheat" on their high school test scores by making the bad students go somewhere else before graduation. So don't take the published scores too seriously.
- There are no Spanish-only schools in Catalunya. There are private French-only, German-only, Italian-only, English-only, but sorry, no Spanish for you. If you are moving to Barcelona so your kids can learn Spanish, boy you are in for a surprise! There some international schools let your children do Spanish as long as your children are not Spanish citizens and you promise not to stay in Catalunya for more than a couple years.
Agora –Large private somewhat less pretentious school that aims for a trilingual education in Catalan, Spanish and English. The school was ranked as one of the top 100 schools in Spain (and second best in Catalunya) by El Mundo. Most of the parents are business people from a Catalan background. There are not very many international students, and don't expect too much help if your kid can't speak at least Spanish. The arts, music (the kids can learn piano, cello or violin) and theatre programs are excellent. During lunch time they offer soccer and basketball (with weekend league play). The kids of the ultracompetitive parents go to the soccer team, so the basketball team is a bit more friendly to foreigners and/or wimpy kids. Despite being big, they are quite flexible about taking your (grand) kids for lunch or picking them up early for doctors appointments etc. The school is now venture capital owned so they tend to nickle and dime the parents for every little thing, especially the uniform. They don't make the kids wear Agora underwear yet, but I'm sure it's just a matter of time. They have a small campus in downtown Sant Cugat called Patufet that is very nice for P3-P5.
Benjamin Franklin – Has a bus from Sant Cugat, so it’s easy to get to. It’s bit of an Americana bubble though, with pretty high turnover from people that aren’t planning on living here for long. They have about 1/3 American, 1/3 International and 1/3 Spanish students. Very expensive, although I expect many people don’t pay it themselves (ie company pays). There's a core group of very nice parents and if you only speak English and want a social life via school, it's a great place to go.
St Peters - In Barcelona, but lots of kids from Sant Cugat go there (there's a bus). We know a couple spoiled brats that go there. Nothing like spoiled brats with finishing school accents.
Lycee Francais - In Barcelona, but has a good reputation. It used to be fashionable to learn French, but not so much anymore.
Swiss School - Heard good things about it. Your kids need to know German though.
Aula - A bunch of our neighbors go there. Looks good on paper (they do really well in science competitions), but if you talk to some of the alumni, it definitely has a dark side. It's extremely competitive to the point of ruining the self-esteem of kids that can't keep up. If you don't keep up, you get kicked out pretty quick. It has one Spanish speaking track, which at first we thought would be great, but it's full of kids of PP politicians and other right-wing types.
Deutsche Schule – Admissions is run by a old-school German woman that scares anyone who has ever met her. One neighbor's kid goes there and is quite happy. Unless your kids have perfect german and/or you have serious enchufe don’t bother. Montilla sends his kids there, what a hypocrite. They have a bus that goes to Sant Cugat.
La Farga, Viaro – Crazy right wing Opus Dei Catholic cult-school. If you meet a family with 8 children in Sant Cugat, they go to La Farga. If you happen to drive by in the evening you can sometimes see a bunch of people walking in circles. (Also, if you are in need of a social group, Opus people are very friendly, in a creepy cult-y sort of way.) Not sure exactly what they are doing. Viaro is apparently the school for the ultra-Opus people, whereas some reasonable people send their kids to La Farga due to higher Spanish language content. The fact that people are desperate enough for a Spanish education to put their children in the clutches of Opus Dei should tell you something. There isn't a lot of teacher supervision on the playground. The other day we were walking by and there was a group of kids sitting off in the forest smoking pot.
Waldorf School - In Bellatera. In Catalan but with lots of international parents, so English speaking kids won't stick out. Much less academically oriented for the first couple years, more focus on imagination, stories, arts, and music. European Waldorf schools more respectable than their hippie granola-eating North American bretheren, and have a very good reputation.
John Talabot - A very nice small concertada school in Barcelona that focuses on a trilingual education (English, Spanish, Catalan). We know a couple people that go there and love it. We decided against it mostly for logistical reasons.
American School of Barcelona – Not in Sant Cugat, but there’s a bus that goes from Sant Cugat at a relatively reasonable hour. The facilities are a bit down scale, but we’ve heard that the school has a very inclusive environment. There’s actually an anti-bully policy, which is (unfortunately) revolutionary for Spain.
Public Schools – With all the cutbacks, providing a good education has become very challenging for public schools. The quality of teachers is generally better than in private schools (you would be shocked at how little teachers get paid at some of the more expensive private school). However, your kids would have to deal with all the problem children that the other schools are not willing to deal with.
Escoles Bressol- We've had a very good experiences with these municipal preschools. They're not free, and it's hard to get into the downtown ones. Don't count your kids learning anything other than Catalan. However, they really teach the kids to be self-reliant. For example, in P2 the kids set up and put away the lunch table, help out in the vegetable garden, etc.
Other concertada schools – usually better than the public ones, and pretty cheap as well. They gotta be in Catalan, although some do clever things like pairing Catalan + Spanish/English speaking teachers together so that kids can learn more Spanish.
Not that I’m encouraging cheating (har har), but just so you are aware that everyone else does it: If you want to get into a concertada school, you need to live pretty close by, otherwise you won’t have the points to get in. Luckily it’s pretty easy to temporarily change your address to a friend’s place that lives nearby. Either get them to sign an authorization form or register your mobile phone billing address there as "proof" to get your empadronamiento changed. If you don’t do this, you basically have zero chances of getting in since everyone else cheats. Some parents in other parts of Spain even get “divorced” to get extra points for their kids to get into the right school.
Here's a post on how the points system works for public schools in Catalunya.