all of the time. I have only done seller financing twice both with tenants requesting it and did it as a favor. So it is not something I am that familiar or comfortable with. If you were ever not in a position to resolve the due on sale clause that would be a bad situation if it were called. Like most things as long the payments are made there are no issues.
I think they will become a lot more popular in the future with selllers that have locked in long term low rates. They will present opportunities for both seller and buyer/investor to benefit off the low loans. I don't think it is the direction I will go as not interested in owning any more single family. But it will be potential opportunity for people that are.
There were lots of investors seeking seller finance deals in 2006-2008. I was aproached often back then. They haven't seemed as prevalent since that, but they will likely come back soon. We have always done bank financing and as investment properties so they are more flexible. Primary loans that become rentals or seller financed properties are not something I would be super comfortable with.