I suppose you have no financial issue in supporting your girl in GH till secondary school. Then you may consider the one with least time for transportation.
I have friends' daughters studying at GH (Primary & sec) and SFA respectively.
As I know, GH is NOT allow the students going out for lunch, even in secondary school... but the studying life is not harsh
For SFA, study life is pretty harsh. Competitions among students are keen as well as for their parents also have much pressure.
many years ago, my daughter was on the same case as you.. choosing between SFA and GH. I picked SFA as it was near our home and less expensive. I also consulted my friend who is a teacher at secondary school, they said.. average SFA student quality is higher and maintained well by SFA, whereas GH was dropping each year. So, I cannot foresee my daughter to be top at the form... so I believe SFA is good school and I let my girl to study there. Now that we have transferred to another top girl school with secondary school at Hong Kong Island. You may want to consider this.. as GH has more homework than SFA.