Apple is a strict meritocracy.
The better your performance; the better your compensation and presented opportunities will be.
The company's reputation for secrecy bleeds into its culture and there is a surprising lack of transparency not only in terms of development, but management.
Your performance is entirely subjective to your immediate manager who is not always suited to managing people. The emphasis at apple is managing products.
Specifically their product. Combined with aggressive scheduling, there can be a astounding amount of infighting and politics.
It is possible to be a pawn in these politics and have information withheld concerning product and company vision.
Work-life balance skews heavily towards work. Expect 60 hour weeks minimum during post release lulls.