@Rafael Ro Traditionally, investors have targeted Class B properties. 

It's not a traditional school building.

I am at 4 now and hoping to average 2 more per year yet ready to quit my traditional job ASAP.  

You can refinance into more traditional loans later, but that initial speed matters.

@Kay S.Assuming you are getting title insurance (which I recommend) the closing costs will be similar to a traditional closing.

The "slow flip" I am referring to was purchase the property in the traditional financing way and then live there while rehabbing and improving (adding bedrooms, getting the yards back in shape, updating finishes, building or adding shop space, etc.).

They provide flexibility and efficiency, especially for experienced investors.How have you found the terms and structure compared to traditional options?

If the houses are in decent shape and could get traditional financing do not sell seller finance.

The mortgage company gets paid off first, then in a traditional sale, the rest minus agent fees and utilities and closing costs goes to the seller.

I have had people work for me for years under this concept and with some very few minor disagreements it has worked out very well, the money saved allowed us to do 3x the work than if we had gone the traditional route.