I'm one of them and I don't see a compelling enough reason to upgrade at this point (iPhone or Android). Siri looks interesting, but it's not a feature worth locking myself into another 24 month contract for.

All the Australian networks are moving to 4G, so IMO it's a good time to wait for the next gen of LTE handsets. As with the original iPhone, I suspect it was just too early for Apple to switch.