Buy another or pay one down

[Jason Smith]

I own 10 properties (7 with loans, 3 owned). I recently sold one I owned at 100% to buy another with better numbers. I got the loan and it left me with $40K. I could pay down a different property and own it faster or I could invest in another. It's a tough market right now in my area as property values have increased. I've been looking in two different markets for 2 months. What would you do? Pros/Cons