Lease to Own? Does it ever make sense?

I put my really cute, affordable listing on Craigs List. It is a starter home...a row house...in Rocky's old neighborhood--South Philly. At $165,000, a buyer could get it with $7000 out of pocket (the required 3.5% FHA downpayment) and the seller could cover closing costs if we boost the price to $170,000 and give a $5000 seller assist. Thanks to the Obama extention of the tax credit, the buyer can get $8000 back once he/she files their income taxes. So why isn't this great deal selling? I got a call a few days ago from a potential buyer who sounds really nice. He claims his credit was ruined when someone hacked into his PayPal account. He is proposing Lease to Own. His mortgage person claims he will be able to buy in 6 months. So no tax credit. My seller needs $1000 a month to cover his mortgage. The house has been on the market since Oct. with only 6 showings. Of course, I need to check the buyer out for myself...have my finance person vet him. If he comes out OK, should I consider this? It is my understanding that 80% of "rent to own" deals do not wind up in a sale. My seller has 2 mortgages and could use the rent payment. Am I nuts to even consider this? Any advice on how to structure it so it makes sense for the seller?