How financially sound the insurer (or the underwriter behind the brand) is, based on an independent rating agency's assessment.
How established and financially sound the insurer (or the underwriter behind the brand) is, and how transparently that's disclosed. This is driven mainly by the underwriter's Financial Strength Rating (FSR) with time in the NZ market and plain-language policy wording factored in around it.
A Financial Strength Rating is a grade issued by an independent ratings agency (most commonly A.M. Best or S&P Global Ratings that assesses an insurer's ability to actually pay out claims, based on things like its capital reserves, reinsurance arrangements and claims-paying history. It's not a measure of customer service or how good the policy wording is, it's specifically about the underwriter's financial ability to be there when you need to claim, including in a bad year with an unusually high volume of claims across all its policyholders.