Cheap and that's it
Pros
Low rent. That's it.
Cons
The whole building smells and is falling apart, there are rats/mice/bugs, the front stoop is always filthy, garbage is frequently not taken out, appliances are old, no matter how much you clean everything in the apartment feels dirty, the hot water in the kitchen takes forever to get hot, in the summer all the heat from the lower apartments rises and by the end of the day it doesn't matter how many ACs you have.
Advice to the owners
Care even just a little bit to invest some time and a little bit of money