I would look at the reasons its in the condition its in.. many make the statement the previous owner let it go to pot.. that's an easy one...
what I have seen if this is C or D class is that they can be almost impossible to keep up and keep rented.. turn over and damage kills the property and you end up in the same boat as the seller is sitting in right now.. I have seen it happen numerous times.
and in those tough to manage buildings PM is not going to save you... many times they are the one's taking advantage of you..