Mortgage or Paid Off?

[Adam Scheetz]

I'm curious as to what are the advantages and disadvantages to having rental units paid off versus mortgaged? For example, spend $50k to pay off your remaining loan or use that money to acquire more assets? My thinking is that paid off [especially sooner] seems smarter so you have no debt and 100% cash flow. But the money spent on that could help acquire more cash flow in the short term. Thank you, Adam