I'm doing a PhD in NZ (also 3-4y). It's nice to hear someone who has similar reasons to mine for doing a PhD. Like you, I'm hoping to get the best of both worlds.
For me, my (engineering) PhD is a chance to take on an entire project. I get to do system-level design, hardware, software, signal processing, user interface, the lot. The thought of spending four years in a job at the bottom of the ladder doing small, well-defined tasks that my manager told me to do didn't really appeal. Instead I get to manage a project, make real decisions, and learn to deal with the consequences of those decisions. I'm not doing it for the sake of any opportunities that having a PhD might bring so much as the opportunities presented by actually doing the PhD.
For me, my (engineering) PhD is a chance to take on an entire project. I get to do system-level design, hardware, software, signal processing, user interface, the lot. The thought of spending four years in a job at the bottom of the ladder doing small, well-defined tasks that my manager told me to do didn't really appeal. Instead I get to manage a project, make real decisions, and learn to deal with the consequences of those decisions. I'm not doing it for the sake of any opportunities that having a PhD might bring so much as the opportunities presented by actually doing the PhD.