I see double digit returns (10-15%) being quoted as common for note investments done correctly.

That exactly how I started back in the early '80's.Interest rates were running double digits & qualifying was a nightmare.

If I were to expect to be inside the unit, I would bring a digital recorder with a hidden mic (which I have). 

Hyperinflation... or at least high double digit rates of increase in the values of the homes.I don't expect that anytime soon.

Through proper diversification your $50K SDIRA could return a double digit return with not much risk allowing you to focus on other areas of real estate. 

There is much more to look at than simply a 3-digit number.

They could go all digital slot machine style and hit buttons on 300 rentals in 1 minute if they wanted. 

I try to help or at least be civil to everyone, you never know, but I do know most aren't cut out to make it in RE, usually it's an attitude issue, but I know some can't add 6 numbers with 6 digits and multiply the result by 12.

With the single digit temps we were experiencing, the hole in the brick let the pipes freeze in an occupied and heated 70* unit.

I'm one of those crazy people that think peoples character and integrity come down to more than a 3 digit number, and trust my instincts.