By "objective" I take it that you mean "opinion-independent", and by "subjective" I take it that you mean "opinion-dependent". This seems to be the distinction, based on the initial question of the OP.
I pretty much agree with Aristotle's general conception of goodness and virtue. This is my opinion and I'll give the justification for my opinion in a second. To summarize Aristotle, goodness is objective. That's not to say that goodness can't also be situational, context-dependent, culture-dependent, or person-relative. Goodness involves the fullest actualization of the potential of a thing. So a "good" knife cuts well, a "good" dog isn't trapped indoors, and a "good" human being is one such that that human being lives in a circumstance and has an inward character that is conducive to human flourishing. That is the general structure of virtue theory, and the particularities of what counts as "human flourishing" are to be filled in by virtue theorists. Aristotle, for example, thinks that human flourishing is a life of excellent rational activity. I would subscribe to virtue theory generally, and my particular view is that that human flourishing is communion with God and the rest of humanity.
So there are external factors and internal factors that contribute to a person's "goodness". A morally flawless person who is severely handicapped is not living "the good life", and conversely a morally base person who has everything they could ever want is also not living "the good life". Moreover, what counts as the good life for a human being is person-relative in its particulars, because we all have different innate passions and personalities. (But "person-relative" does not mean "contingent on perception", so what's best for a person is still an objective matter!) The good life for one might be to become a master chef, the good life for another might be to become an ascetic monk. But there are general features of the good life for human beings, such as living in community, loving others, being loved, being in communion with God, being virtuous (e.g., possessing generosity, magnanimity, courage, etc..), exercising rationality and one's intellectual faculties.
So, justification for my opinion: there is a set of ethical questions that we need good answers to:
- What makes an action right or wrong?
- What makes a person good or bad?
- What makes for the good life?
- What makes a thing valuable in itself?
- Why are human beings imbued with special moral worth?
- Why are human beings obligated to help those who can't help themselves?
- Why be moral, even when it's not in your self-interest to do so?
When you set up the list of major moral theories on offer--JS Mill's utilitarianism, Kant's deonotology, natural law theory, moral nihilism, moral relativism, Aristotle's virtue ethics--I think Aristotle's virtue ethics gives the most coherent and persuasive set of answers to the questions above and makes the most sense of our moral experience. I think it's tempting for materialists to think that there is no real value, no such thing as goodness/rightness/"the good life" when they presuppose that all that exists is matter and energy. So much the worse for materialism, if that's what it entails. I think our moral experience should be taken seriously, and any worldview that implies that our moral experience is illusory should be immediately suspect if not outright dismissed.