never let either dominate. depending on situations sometimes the heart is right, other times the mind is right, den oso both can be right or wrong.
heart is not devoid of logic, eg, for the greater good. how the good is defined will depend on the heart. at times a decision process takes into account lots of other factors that is non-conformist in nature. like choice of colour, blue over yellow.
mind's logic may be more surgical (eg, in controlled environment more easily explained & understood) obvious (eg, 1+1=2).