Target Retirement in Taxable Account

Hello,

I've maxed out all of my tax-advantaged accounts and for simplicity have been contributing to a taxable account purchasing VFFVX. Since this TR fund includes bonds, I am thinking of just exchanging for VTSMX. Is this a bad idea? It seems VTSMX has been down slightly more than VFFVX in recent history, and I've had the account for less than a year.