However, often you can make more cash flow from them compared to homes since you have 4 doors under one mortgage and even when you have a vacancy there are other tenants still paying which helps cover your expenses.

I figured if I use a different company for several properties it will be a great way of comparing them. 

To see if the expense of a rehab is worth doing look at sold listings near the property and compare bedrooms and comps of three bedrooms VS four bedrooms. 

Understand the fees involved and calculate the total cost for an entire year of management so you can compare the different managers.

I dont really estimate capex and repairs per se, but my condos have way lower capex and repairs compared to my single families.

@Gregory Hiban This thread wasn't about comparing Philly to the Poconos.

2-4 units are still considered residential properties and therefore are valued based on comparable sales and not NOI and cap rate.

I bought an SFR cash because the comparable sales within a mile were around 70k and the "as is" close now price was 20k. 

Are there any reliable websites or databases available?

Population characteristics (www.usa/com/rank) Population:Population growth:Population density:Population compared to other cities in state:Fast growing area?