Seller Finance - Is it worth it?

[John Martinez]

I am looking into a potential investment property that is in bad shape. The price is reflected of it and I would actually try negotiating the price down a bit more due to the amount of work that has to go into the property. 

The current owner is allowing seller financing with a $20K down payment. If I can get it for what I want to and the rehab cost I estimated are accurate it can potentially bring between $15K - $25K in profit, the only thing I am unsure if is "seller financing". 

Has anyone done this already? Can you share your experience?