Can anyone shares why pick the internationl school

hello surewinla,
In my opinion, if point 2(Government Policy) is your concern and $$$ is not your concern, IS is more confident to have a happy life.
Although someone will say that local schools still have a lot of good students, sorry, it cannot contribute their achievement to the Educational System : they deserve to be good students only because of their talents.
As long as students are going through the route to HKCE/HKALE /local Us(going to reform again...combine into one exam...), no one can get rid of experiencing such riot and pressure, No matter you are studying in Chinese / English local schools.
Anyway, if you think your boy is smart enough to take the challenges and you do proud of being a top local school parents, why not DBS?
I believe you have already had your decision in your mind.
Good Luck!