Invest in another rental property or rent out my basement?

[Gilbert Cataluna]

Hello,
My name is Gil Cataluna. I have one rental property that I've been renting out for 2 years now. I built a brand new house last year which I am currently living in. Both homes I believe have at least $100k in equity. I'm about to get my HELOC and seeing whether I should use it to buy another rental property, or use it to finish my basement in my current home? If I finish my basement which is roughly around 1600 square feet, I hope to rent out for at least $1200-$1500. If I can do that, my mortgage will be mostly paid for every month. Please let me know what you guys would do, or any advice you can share with me.

Thank you,
-Gil