Watch out for rent-to-own in general.
In a conventional mortgage, you own the house, but the bank has a legal claim to it because they lent you money. While you’re paying off the mortgage, you’re building up equity in the house. If you stop paying or need to move, you still have the amount of equity you’ve already built up; since the first few years of a mortgage are mostly interest payments, this may not be much, but it’s something.
In a conventional rent-to-own setup, the finance company owns the house, and you have no legal interest in it aside from your tenancy. If you stop paying or need to move, you have no equity built up. You’re out any payments you made.
Rent-to-own situations strongly favor the bank or finance company.
Now, what you can sometimes do is enter a rental contract with the understanding that if you decide to buy, the money paid as rent will be accepted as the down payment. A friend of mine did this with a house in NYC that he thought he might want to buy. Of course, the rent was five figures monthly, and so he had accountants and lawyers to make the deal for him, so it wasn’t a conventional rent-to-own scenario.