Use cash flow to pay off my SFR rental or invest in the S&P 500?

[Matt Wells]

Hello, I have around $550 a month positive cash flow from a couple of SFR rental properties. I'm debating on whether to use the positive cash flow to pay off the SFR principal or to invest it in a Vanguard S&P 500 mutual fund. It would be helpful to hear some pros and cons of each.

[Adam Bileckyj]

What puts you in the strongest position? I am doubling down on stocks right now because it's easy while I am building my firm and the market is way down. In a year or two I will probably look for a property.