Selection of a finished project for finished results
Before you make the final decision, look at other houses built by the contractor, whom you are going to hire for work. Choose once on the weekend to one of these houses when its homeowners will be free from household duties and talk to them.
Inverse with them whether it was easy for them to work with your contractor if he was honest in construction calculations and whether the workers were tidy and punctual? People usually willingly tell if they like their house, or, if not, why.