Hi Enchanted,
I'm also with Australian unity for top extras. I don't have hospital or obstetrics. I decided on no obstetrics and to go public because the rates of Caesarian births and interventions are way lower in public hospitals.
Before choosing cover, I added up what I'd spent on all medical, optical, dental, massage etc so I got a really good idea of if it would be worth it and how much I would save by having cover. It worked out I was far better off with private health insurance that without.
So I LOVE my health insurance! Because I did the calculations, my insurer has payed me way more than I've paid them!
So I suppose my tip would be, doing the sums is really worth it, so you know what kind of cover you will be shopping for. Good luck!