Yes, it's subjective, but not entirely. After you've done it for a couple of decades, you start to have a sense of taste, of aesthetics. Some things seem beautiful, and others ugly. It's "subjective", but it's also informed by two decades of practice, so it is far from being purely subjective.

Robert M. Pirsing discusses qualia in his writings. One objection raised by his antagonists is, “quality is just what you like", echoing the idea of broad subjectivity you raise. Yet there is broad agreement on what counts as quality. Among the aspects we agree on is complexity and subjective cognitive load.