The IRR or CoC or ROE all are better indicators of quality of the investment and how it compares with other options.

ROE and IRR, etc will tell me more about the PROFITABILITY of a property. 

So if I would purchase these duplexes would I be constantly overturning them/ sitting empty.My number: vacancy 8, matanance 8, with property managment 8, capex 6, and cashflow is 200.  

Leverage out tasks to others.Liquidity eventsMost investors focus on ROI, worth consideration but even more so is ROE, return on equity.

I am looking into acquiring a property which promise (at least on paper) positive cash flow with cash-on-cash ROE of 17%.  

This keeps your cash out of the deal and pops your ROE, IRR, or any other metric you use as a hurdle rate for the project.Buying subject-to generally ups your purchase price above what it would be with an all-cash offer so all of the scenarios need to be modeled for each type of transaction to see which one makes the most sense.

., whip out the contract), the faster a judge will overturn a lien.Knowing a contractor faces stiff penalties for filing a false lien doesn't make me feel any better while I'm being restricted from selling my house.Now for all the government benefit programs, all you do is say where is the employment agreement, these guys are self employed, where did they work last?

Arizona, for example, recently passed a state law that supersedes and overturns any local bans on Airbnb. 

If I pay cash for a home, I have 100% equity working for pennies on the dollar, giving me a very low ROE.  

Its not always about trying to maximize cashflow, ROE, etc.