Abarca works through Century 21 Arizona Foothills, and if anyone is looking for real estate in this area I highly recommended his services.

I've called him about several issues that have popped up in the last few months with this turn of the century property.  

After you address all the issues of a half century of neglect and poor property management, you can get market with good paying tenants.  

I use 7% for the century old homes.

Were your unit my unit and your predicament my predicament this is what I would do: Step one: Call the main line for all the major firms in your area ( Century 21, Keller Williams, Coldwell Banker, Smaller Local Names).

I know this is unjustified and flat out unfair but we are all entitled to our opinions :-) This is another reason why I would lean towards Windermere or century 21.

We had an early 20th century bungalow whose downstairs was "updated original" and the upstairs was essentially just a large loft.

His list is full of vacants, which I don't necessarily disapprove of, without a second motivating factor (e.g. divorce), I would never pull a list of addresses based solely on vacancy - especially in a city like Philly, which is overrun with early 20th century dilapidated vacants. 

Are other houses reasonably well kept up (lawns mowed, painted this century, lack of dead cars in the driveway, etc?) 

Most 4-plexes that come up for sale are located around the Hikes Point area and constructed in the 60's to 70's or are around UofL and are turn of the century SFR's converted to multis.