Short answer: If prices rise faster than the premium costs, buy sooner. If prices are flat, save 20%.
It depends on your timeline and the market. If prices are rising fast, buying sooner with 5% might save you money even with the 1% premium. If prices are flat or falling, saving 20% avoids the premium and gives you better rates. Do the math for your specific situation.
House Price: $600,000
Option1 Deposit: $30,000 (5%)
Option1 Premium: $5,700/year
Option2 Deposit: $120,000 (20%)
Option2 Premium: $0
Break Even: If house rises $5,700/year, Option 1 wins