There is just no way that any perceived marginal improvement in the quality of care on an individual basis warrants an off chance of maybe being bankrupted. I can't say I've ever found the quality of care of be poor or unacceptable. It's always been available and served me well.
I kind of liken it to being forced to drive an $80,000 BMW as opposed to being provided with a reasonable Toyota that does the job.
The economic experiment has been tried and the US is on the wrong side of it.
I'm aware however, with the rescue helicopters there can sometimes be complications because at the end of the day, someone needs to pay - but as an accident, everything's covered under ACC anyways. (and: http://www.police.govt.nz/faq/if-i-get-lost-and-need-search-...)
I have lived here for 9 years and although have paid my insurance diligently i always get anxiety at going to the doctor's office.
Doctors (GP) visit typically costs me around $40-50NZD, thats likely on the high side, Children are free / fully subsidised.
A&E visit would be $50-100NZD
Most all injury related medical costs are covered or subsidised by ACC.
Specialists Appts typically cost ~$200 per visit
Private health insurance, while in no way "required", is still offered by the bigger employers and will see better outcomes for elective and non-urgent surgery and is priced in the hundreds of dollars per year for "basic" coverage if you wish to purchase as an individual.
Edit: clarified coverage for visitors