Pros
Overall, the employees are very nice, very smart, and very dedicated. There's an optimistic spirit. You feel like you're a part of something, particularly during product launches. Look around and you'll find some development opportunities through brown bag lunches and employee development offerings. Seek out mentors. But know your boundaries, too.
Cons
Apple seeks employees who excel in their areas of expertise, but depending on which department you end up in and which manager you get (they change often and there's layer upon layer of hierarchy), you may find yourself in a narrowly defined job with limited ability to use your existing skills. You also might not get an opportunity to develop new skills. Expect to work long work hours. Unlike a startup, you don't have much hope for advancement -- if you start as a drone you might remain a drone. You have to learn the political landscape, and it takes a while. Some people really thrive there and can move around. Others stay and take what they're given. And a few get kicked off the island.