better than the 4-5% you're paying in interest on the mortgage. For most people, the best strategy is to focus on paying off all the consumer debts, like credit cards, auto and student loans first. Once you pay those off and all that's left is the mortgage, redirect all the money that was going to debt towards building your retirement account.
Keep paying the mortgage (with that super low interest rate a tiny tax benefit from the interest you pay) and double or triple your retirement contribution. If you do it right, when you reach retirement you can pay off the remaining mortgage balance from that account and free up some cash flow to help sustain you in retirement when your income is likely to be less than when you were working.
No debt is *good* debt, but a mortgage is about as good as a debt can be. Focus any extra resources on the *bad* debts first and leave the mortgage til last.