On a national level, ICSE and CBSE are the two most prominent education boards. Schools that are affiliated to both these boards provide top-quality education that is in accordance with a curriculum that conforms to rigorously high standards. However, it should be noted here that both the ICSE and CBSE boards have vastly different syllabi. So, when choosing a school for your child, it would be helpful to understand the direction their future education or their career path will take. For example, the CBSE syllabus is more practical for those seeking to pursue higher education in the sciences or engineering, while the ICSE syllabus is a better choice for those seeking to pursue higher education in the arts or the social sciences.
So, to summarise, there is no objective yardstick to measure better or worse, but rather, the difference in syllabi as well as focus on subjects are what should be a determining factor in your choice of schools. This article talks about the differences between both the ICSE and CBSE boards. Do have a look at it. It’ll give you a better idea of how the two systems are like.