"If you are good at investment" <<This is a BIG IF.
Actually We invest moderately on stock/401k/529, what else? The the problem is that: due to some new rule from a particular lender, a house with less than 2 yr rental history beomes our liability, and that affects our interest rate when refinancing our primary residentcy. This is why we are considering pay off it. We just do not know any string attached.