I work at the American School in London. Have you spoken to anyone in our admissions yet to see if there is any space? We tend to be VERY over subscribed, though sometimes openings come up.
There are a lot of positives about the school and most families LOVE being there. Obviously there are negatives like any school. The big positive is that it is a huge community: parents are encouraged to take part in the school in many different ways and there are some wonderful programs for the students. The school is quite competitive and can be tough for an average student. We have the best SLD program I've ever worked with and a great counselling team (I'm one of them, so I'm a bit prejudiced). We have things for sporty kids, musicians, actors, etc.
If you have any specific questions, please feel free to pm me.