Hello,
I would like to give you my personal advice as I am a FIS student myself. During Primary, there are no tests and the children are not graded severely. There isn't a heavy homework load and it is true that the primary mandarin standards are not very high. However, the teachers are very likable and there is a strong link of communication between teachers and parents. Secondary is very different, there is a lot of homework and tests. For the first two years of Secondary, the teachers start to build up a foundation in general knowledge of subjects for the students. In the third year, Spanish is introduced and the teachers start preparing the students for the IGCSE course. In the fourth and fifth year, the students enter the IGCSE course and in their last two years they participate in the IB programme.
It must also be taken into consideration that if you want your child to expand in his roots and not only focus on academic studies when he is older but also in subjects such as Design & Technology, Food Tech, Drama, Music etc, FIS Secondary does not provide these subjects for the IGCSE and IB courses.