Comparing mixed orientation solar panels to non-mixed on a Brooklyn Solar install
Ask them for a total annual power generation estimate using NREL PVwatts. What you want to see is how many kW-hr of power each system should generate in a year under typical weather conditions.

The two systems are going to perform drastically different given their orientation and inverter arrangements. Depending on how the panels are strung together this could be a very large effect. Comparing the total # of kW is not sufficient.