I think it should depend on your kids personality. I personally think LSC kids are more aggressive and you need to be very initiative to get more opportunity there. All kids are smart in both schools, of course.
My son is quiet type and not excellent in sports. At QC, he now becomes more outgoing, swimming, table tennis etc and enjoys school life so much. They have good relationship with students in higher forms too, just like their big brothers...
[Both schools are good.
If both schools accept your boy, the system will allocate your son to the first choice.
In Academic side, LS has around 400As every year.
(highest: around 500As and lowest: around 350As).
I think QC has similar achievement.
In Sport side LS is better.
In Music and Art side, QC is better.