Most comparison pages stop at "monthly payment." That's a mistake. The real difference between FHA and Conventional is what happens to mortgage insurance over time.
If you put less than 10% down on FHA, you pay MIP for the entire life of the loan. 30 years. Every payment. The only way to drop FHA MIP is to refinance into a Conventional loan or pay the loan off.
Conventional PMI is different. By federal law (the Homeowners Protection Act), PMI must cancel automatically at 78% LTV — and you can request cancellation at 80% LTV. With normal home appreciation and amortization, this typically happens in years 5-8.
So the FHA borrower keeps paying MIP at month 360. The Conventional borrower stops paying PMI in year 7 — and pockets that money for the next 23 years. That's not a small number. On a $400K loan, it's typically $30K-$60K of extra cost over the life of the FHA loan.
If you'll own the home less than 5 years: this difference doesn't matter much. FHA's lower rate often wins. If you'll own 7+ years: Conventional usually wins on total cost. The decision tool above shows the break-even year for your specific file.