Conundrum: Next Financial Move After 2 Properties

[Lee G.]

Summary question:  How would you allocate by extra money saved from my paycheck by percentage between 1) stock piling cash for a 3rd rental property 2) paying down existing mortgages ( I currently own 2 mortgages that have low interest rates) or 3) investing in traditional retirement accounts including ROTH IRAs, etc.

Brief Background:

I own 2 properties which both have low interest rates.  I live in one property, but I plan to rent the property in the next 1-2 years which would be my second rental property.  I am now 9 years into my career and continue to see good pay increases and expect this to continue. 

Part of me really wants to pay those mortgages off, but I know statistically I could do better investing in the stock market/real estate.  I am interesting in continuing to expand to a 3rd investment property but I am having trouble seeing how the best way to go about it.  Leveraging up does not appeal to me especially considering my income.  I do not see any reason to take on unnecessary risks but then again I do not consider myself a chicken little.

Thoughts?