What Slapshot said is about it. Although there are some good parts. The Maths in HKG schools are amazing compared to where I live (Australia). HKG Students that come and study in Australia have some real good Maths, the stuff we're learning in Maths right now, they learnt long time ago.
There ARE parks in HKG but I'd not as many as here in Australia and other parts of the world. The parks there are enough for what you need (Fitness) but it'd be better to excercise in a non-polluted area.
I thoroughly recommend you stay in Canada or perhaps come to Australia
The school level here is ok but to me a bit low (That's why I do some extra study at home). The schools fees are nice, living here is very nice (WIth large parks etc) and the air is really nice here.
Hope this helps,
Capt. J