Owner Financing..Good Deal or Not?

I am working with the owner of a home that I am now renting to do a possible owner finance deal. My question is, is this a deal or not? We are considering putting down about 10K. And then doing monthly payments with the agreed upon interest rate, etc. factored in of course. My husband and I are only considering this option, because it frees us up on paper to move ahead on plans with our Farm, which might otherwise be hampered with a 200K+ mortgage on paper. It is our intent to pay off the Farm Projects in the next 2-3 years, and then convert our Owner/Finance Deal into a traditional mortgage, with a traditional mortgage lender. It just feels right as far as the long-term to both us the purchaser and for the seller. We want to be fair to the seller (although it is definitely a buyer's market right now) and really want this to be a win win situation for everyone. The Seller was left the house by her Aunt, and I'm not sure if they still have a mortgage on the home, how will this affect our deal, if they do? Is a lease to buy option better, and if so, does it usually get a smaller down payment? Help, there seems to be a lot of varying opinions, and contradictory information out there. Thank you in advance to anyone who has real concrete advice on the matter. I live in Virginia.