I'd say the first question is, do you have a decent down payment amount? So many people we speak to think that seller financing means no down money - a big misconception.
Sellers will have quite a bit of closing costs, so they typically won't close without from 5-20% down.
Even in this market, if a seller can afford to provide seller financing, that menas there is no mortgage (as they could not sell it to you if they owe on it until that is paid off first). If they own it outright, they can also typically afford to wait out the market.
What we've seen is most seller financing is for people with good down money but perhaps not great credit (so the seller takes a risk instead of a bank). Or, the buyers may own a business and not "show" great income but can afford a home. Sellers typically also charge a bit of a premium on interest rate (over a bank) because of this.
That all said, what most people looking for seller financing actually should be looking for is a lease option - basically renting a home with the option to purchase at the end of the rental period. Many times, a seller will also "put some money away" (from the rental funds) as a down payment if the option is exercised.
The problem with both of these methods is the lack of options (not many sellers want to do this and most have a mortgage). Sometimes its better for the potential buyers to simply rent until they get their credit back in shape or a sufficient down payment.