My approach is to take a few minutes per quarter and make sure it is accurate by manually checking my true competition and adjustmenting prices accordingly. 

The law does NOT apply to landlords:With less then 5 rental unitsThat live in one unit of a duplex and rent out the other unitThat rent out rooms in the home they occupySo, landlords can no longer state in their rental ads, "Section 8 not accepted".The reverse is also true, "Section 8 only", cannot be used.We've always recommended screening S8 tenants the same way as cash-paying tenants.Landlords waiving application fees and/or security deposits only for S8 prospects may also be violating Fair Housing.

If that were true, then an investor putting 20% down would snatch it up. 2.

I agree with @Michael Baum, are they true comparables? 

If you ever see someone offering terms that are too good to be true, you might as well just post your SS# and banking information on IG.

Yes, you will need a cash or PML to buy the house, but it is true of any real estate transaction with the exception of wholesaling. 

I was taught this my the principal of one of the largest industrial REITs in the country and it has always proven to be true.

i understand a true duplex might be a lot more expensive, but i think it's at least worth continuing to research and keeping an eye on.and sticking to my original point, OOS can be tough. 

What are true returns for comparison, before or after Income taxes? 

Personally I am thinking 1c. 1c but 2 being more true then we would like.