The best thing is to visit the school and watch the kids, parents, nannies. How do the interact, are they friendly, well behaved, polite?
When you start to spot kids in uniforms in the local shops and transport, you will start to get a feel for the cultures - there are some schools that have (generally) rather nice and friendly kids, and some that are rather, well rude and quite pushy!
Also Google the head, owners, key staff and school for reviews, news, gossip and opinion. Visit more than once, observe and ask lots of questions. Its not all about academics - a happy childhood will learn. Sone schools are just exam factories.