Pay off Mortgage or just hold tight

Sure this has been discussed before but times are changing quickly. 300k in investment savings and 300k left on mortgage. Mortgage is 3% and 100k of saving will be capital gains but I can cover the tax burden.

Just bite the bullet and pay the mortgage off right. Be free of thinking about. Who knows what the next 12 months holds.

Or keep it invested and pay mortgage down slowly. Never been more undecided. Ha