I am gonna go with turf conditions and firmness. Pacific Dunes, Kingsley Club and Ballyneal are all tremendous golf courses in their own right. They all share one common characteristic; firm turf. Man, I just love playing off those surfaces, which allows for so many shot options, both into greens as well as off the tee and around greens.
At the same time, I've played many a course with a great layout that was more or less destroyed becasue the ground was water logged, and you couldn't use the ground. I realize that Arcadia Bluffs has taken a beating on this site over the years. I love the layout and the vistas of Arcadia, but I think the course would be so much more fun, and much more well regarded (especially on this site) if the turf resembled turf conditions at say, Kingsley Club. How fun would that course be to play on turf like that?
After turf conditions, I would go with quality of greens, since so many shots are played around greens in a round.