Beneficiary flexibility (I know that none of us are going to die, but some folks manage to make it happen
). Do some research on stretch IRAs and non spouse beneficiaries for 401ks. Lots of 401ks have restrictions.
You can probably find the same mutual funds in an IRA (heaven knows the mutual fund companies would gladly manage the money in an IRA too).
Just remember this: your company chose that 401k provider without ever asking your opinion, so don't think they don't have the power to change again some day without your approval.