It was driving me nuts cause I understood the basic framework but not the details which is what he is going to want know and understand. 

The stuff that sits tends to be over priced junk in junk areas, or that have some issues with the listing, curb offers or what have you. 

Older buildings with older systems: plumbing, electric, HVAC, roof, tend to have more maintenance costs than newer properties.  

STR I would highly recommend not to focus on as first investment: also there, my partner is a superhost and we have been managing Airbnb for years and the last year has been pretty funky: people tend to book last minute and you risk to be cash flow negative starting brand new.

Class C properties, not saying these are Class C (I don't know), require a lot of EFFORT, but beyond that, lower end properties tend to have more turn over, higher wear and tear expense, and longer vacancy if you hold your tenant requirements firm.Lastly, it is simply overpriced.  

It tends to be much easier to raise money and oversee the property with passive investors whose only role is to write you a check than with active ones who will manage the property with you and expect decisions to be made by consensus.

That is why you tend to see builders offering such a big "Builders Credit" it’s because it's "Ghost Money" it really doesn’t matter or exist to an extent.A builder can go into an area build 20-30 homes for example, buy the first 2-3 homes paying top dollar so they can set the market sales.

In my experience, tenants who are paying $300 in rent tend to react more negatively to these things and I've had issues with getting them to leave peacefully, but very broad strokes. 

The taxes, insurance, legal, upkeep, vacancies will drive you nuts if a few hundred dollars ruins your day. ;-) When foreclosures are common, (which they are not right now), I send out two thousand letters a week.

I have a lot of clients in KC, MO too which I find tends to offer better upside, newer construction, less cash flow, but better overall macroeconomics.