Not to mention managing properties in the C or D class areas can have it's own set of challenges and expenses associated with them.

You can also look at which ones may have a better potential sell versus COR - cash out refinance.If you incorporate a good agent into the mix you might be able to get the timing down to sell and purchase using the 1031 exchange to avoid the tax hits.

Moral of the story - Top 4 MSA's still good horses to bet on?

If they are, are you in the world of hard to collect, hard on the property, high turnover "C" or do you have a nice niche where the most reliable tenants in that area want to be and take some pains not to leave?

Plan to add value to a C or B. 

I can certainly believe a C or D class unit might not have laundry hookups or appliances.

***Only exception is if an owner has plan & funds to reposition Class D to Class C or higher.https://www.biggerpockets.com/forums/776/topics/960183-what-they-dont-tell-you-about-cheap-rental-properties?

Would local investors consider these C or D neighborhoods. 

Like mentioned above DSCR is most likely your best bet on the next property unless your intending to purchase for primary use. 

***Only exception is if an owner has plan & funds to reposition Class D to Class C or higher.https://www.biggerpockets.com/forums/776/topics/960183-what-they-dont-tell-you-about-cheap-rental-properties?