Usually its because there is a lot of debt risk. when interest rates went up a year or so ago I lost over 300k in sydication projects I was a part of because I didn't understand this concept.

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with little, maybe even negative, relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560 (almost 30% probability of default), little to no good tradelines, lots of collections & chargeoffs, recent evictions.

It's the concept of buying the debt attached to the mortgage rather than buying the house. 

>The likely rent I'd get in this area will cover half my mortgage payments at the momentI have done all of my brrrr in different market and I have the same issue that after a refi to extract the value add, my high LTV property at current rates is large cash flow negative (not as large as only covering 50% of the mortgage).  

Interesting concept!

Not sure how many PMCs you've had bad experiences with, but we'll take exception to:"Then do a thorough research on tenant applicants (note: leaving this to a PM may be hazardous to your financial health)".BP seems to have more threads about screening mistakes by DIY landlords as opposed to PMCs.Now, if you'd have mentioned Maintenance, you'd get no argument from me:) Even the PMC industry acknowledges maintenance as one of the biggest challenges.Rereading my post, I kinda see how I sounded negative toward PMs.  

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with little, maybe even negative, relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560 (almost 30% probability of default), little to no good tradelines, lots of collections & chargeoffs, recent evictions.

@Jordan Meltzer unless you find a screaming deal - a Class A property won't cashflow for 3-5 years.Class B: 1-3 years.Class C: most investors don't properly understand the risks, so should stay away from them.So, you may need to deal with negative cashflow, but plan on appreciation increasing your wealth.

I understand the concept insofar as if I'd purchased the property, the basis would be what I'd paid it.

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with little, maybe even negative, relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560 (almost 30% probability of default), little to no good tradelines, lots of collections & chargeoffs, recent evictions.