Bias is a prejudgment called a prejudice. A prejudice is biased in favour of what we judge to be right or wrong, good or bad, beneficial or detrimental for ourself. With a relative dual reality perspective of life, I am biased towards opposing genders of emotional energy and like polarities of thought energy. My biased choices, by definition, will put me out of balance with my true preference.
Preference is a sovereign choice. I am a sovereign entity when enabled by my own preferred choice. I prefer to make my choice as a sovereign entity than to follow the influence & bias of an external authority. Preference is a choice of those who prefer to follow their own inspired authority.
Preference is an empowered personal choice, whereas bias leans in favour of others.