Short answer: No 1% premium, better rates, less total interest, price fall buffer.
With 20% deposit you avoid the First Home Loan premium, get better interest rates, pay less total interest, and have a buffer if house prices fall. On a $600,000 house, 20% deposit saves you about $5,700 per year in premiums alone. Over 30 years, that is $171,000 less paid.
House Price: $600,000
Loan At80: $480,000 at 7.0%
Loan At95: $570,000 at 8.0%
Monthly Difference: ~$750/month
Thirty Year Difference: ~$270,000 total