What makes a "good" cigar?

[Habanos2000]

We regularly talk about what our favorite or not-so-favorite cigars are and I was wondering, what exactly makes a cigar "good"? As we accept the givens that 'good' is subjective and that consistancy within a brand and vitola is anything but, why are some cigars pretty much always ranked better than others?

Specifically, do certain brands have access to better quality tobacco? Or do certain brands simply have better blenders? Could Fonseca put out a Cohiba level quality cigar if they wanted to, or are they just doomed to being one of the low tier brands?