In my opinion and experience I recommend people to join their kids in good ICSE schools or in top 5 CBSE schools upto 5th class. After 5th class parents need to think about what next. As I said earlier in this same forum there two types of schools.
1. Competitive Curriculum schools
2. Non -competitive Curriculum schools
Again in both these types of schools General tier schools, Middle tier schools and premium tier schools and super premium school--its all depends on fees, infrastructure, ground, and community similar to our hotels normal to 5star...etc
Competitive schools goal is to drive the students full time into competitive learning and practice----In these schools no time for sports. These schools goal is how many rankers we produced in the top competitive exams. These schools have own integrated curriculum which is more than any board CBSE or ICSE or State
Non Competitive schools generally go with Board curriculums and a bit of sports activities in schools if there is ground or else other activities.
In any school you can find some smart kids who have good IQ levels. These kids are smart enough to understand what the teacher says and they can imagine subject concepts and understands well. If these kids are joined in competitive schools , they can perform much better than being in the non competitive schools. I can say some advanced level teaching and practice will be there in competitive schools.
Another important thing is, in competitive schools you will find all types of community from the poorest to richest and from non english speaking to posh English speaking. In competitive schools non MPC or non BiPC subjects are very lowest priority, because they spend 90% time with MPC and 10% with Non MPC (Please someone correct me if I am wrong).
Competitive schools generally starts their core curriculum from 6th class (Eg. Narayana e techno, Narayana IIT olympiad and Sri Chaitanya IPL, KKR Gowtham..etc)
If the kid is smart enough, better IQ , good motivation and have big goals like IIT or Medicine and needs more practice---go for Competitive schools (non premium or premium schools)
ELSE go for the rest of schools depends on your community requirement and financial ability and preferably nearby your home
* some parents tell me that their kids will be back to USA after writing SATexam...etc--In my opinion SAT is also a competitive exam
* some parents tells me their kids will go back to USA for studies but we need our people in at least 2 sports activities to get an admission to better school in USA. ( I dont know about it)
Finally in my observation from AP ,
Most Kids from ICSE Board schools are strong in English Communication, Writing and debating and strong in Science and social studies
Most Kids from CBSE schools are strong in Maths and Science subjects but not as good in English compared to ICSE kids
Most Kids from State boards are Very strong in MPC/BiPC subjects but very less in English communication and unable to compete debating in English with ICSE or CBSE kids
I may be wrong too, If so please correct me