If you are under age 59 1/2, you will get hit with an early withdrawal penalty of 10%, plus pay regular income tax on it.
So if in the 25% tax bracket and 10% penalty plus state taxes (if in a taxed state), that can be approx. 40% in taxes. Personal decision, but that is a lot of taxes, when you could pay extra on the mortgage and crack it out shortly.
Below is a link to the tax brackets for 2017 (based on current tax law).
http://www.savingtoinvest.com/federal-irs-tax-brackets-tax-rates-and-other-tax-updates/
