It's a high stress, demanding job. Great work is usually rewarded, but Apple does have its politics. Talented engineers I know are well rewarded and recognized internally, but other engineers have been shafted due to politics or the bozo-ness of their particular department or team.
That gossip is best left unsaid, but my advice if you are looking to work at Apple - choose the team you join carefully. Apple's most secretive teams are also the most talented and brilliant folks I've ever met. But they work hard to be friends of Steve.