A greater percentage of Harrisburg is "ghetto" than Philly, in the textbook definition of the term (a city section where poor minorities live). Harrisburg has more people below the poverty line, and Harrisburg also has a black majority. Philly has far more stable urban neighborhoods with middle class people.. although I will say that part of East Harrisburg is diverse, only because there aren't enough different groups of folks to segregate enough.

But Harrisburg is sort of a government town, so it's kinda like DC was 10 years ago... rich people working for the government and poor people not working for the government. Both Philly and Harrisburg have bad public schools and higher crime than they should. Not as high as DC though.

Harrisburg is about 2 hours from Philly.

realtor.com is giving you the prices for DC as a whole, not NW and downtown. They're not on crack, they just aren't picky, basically. You can find a place in the SE or NE corners of DC for as cheap as you can in Philly. Ever been to neighborhoods like Anacostia or Trinidad? They're rough and not as expensive as many people are paying in Philly. The NE corner of DC is crazy expensive, but there are tons of low-rent, high-crime "ghetto" neighborhoods in DC. I know Philly's definitely a "better deal" for the price, but that's not factored into the price because it's subjective. They're not only looking at the nice neighborhoods, they're looking at the bottom of the barrel neighborhoods where nobody chooses to live too.