I was employed at David Jones for a period. From memory they take Christmas casual positions around August each year. I am unsure about ongoing positions.
Based on my experiences, and also similar comments by others, they don't treat their employees very well. They are also fairly inflexible about hours. Myer is far, far better. They treat you much better.
Of course, David Jones has the "prestige" element that mindless idiot customers are drawn to.