Opinions of St. Johns and ISB (Brussels)

Our family is contemplating a move to Brussels. We have two boys age 8 and 13 brought up in the American school system. We are looking at St. John's International School and the International School of Brussels. Has anyone sent their children to either of these schools? I can find some feedback out there but not too much. They are the schools I can find the most information on. Does anyone know of other English speaking schools close to the Mechelen area? My husband will be working in that area. Thank you!