Computing rental amount

[Alan Duff]

I'm a newbie working on my first deal. Looking at a duplex that is 2Br/1Ba. Craigslist yields $625 for a comparable unit in a stand alone duplex up to $775 for one with a fireplace and basement. Units in complexes in the area run from $660 to $724 for the same 2/1. Square footage is comparable for all.

The property I am looking at has a carport for each side as well as a sunroom on the back for each unit.  Fenced in back yard with divider fence.  One side is rented to a long term (10 years) tenant for $600 and the other side is vacant.  What should market rent be?

Thanks