I grew up in the duffys forest area and went to high school in st Ives, so I know it very well.
Honestly, I would not move from where you are.
Yes, st Ives is very lush and green. For me, that would have to be its only possible appeal.
Tillytake2 is correct. Large South African and Jewish population- they are very different to the people you would find on the northern beaches. Snobby is a nice way of putting it, in my experience of the suburb.
The shopping centre is nice, but try and shop there without being shoved and pushed. There are plenty of parks and ovals and some good schools too, depending on your religious preferences.
While it isn't on a train line, they have buses that take you straight to Gordon, 3-4 mins away.
I went to an independent girls school and really would recommend it to anyone.
Sorry I know I'm not painting it in the best light, but I honestly would consider staying where you are. Love the beaches