Pros
Smart people to work with, great pay and benefits--you can essentially carve your own niche if you have enough ambition and can work with the right people to get where you want to go. You will have to put in LOTS of extra hours, but travel opportunities abound and if you are not limited by family obligations and have extraordinary drive, you can go as far as you want to go. I met a number of extraordinary people there, some who will be friends for life. The informal Apple alumni network has also been extremely valuable in my post-Apple life.
Kontras
Long hours, poor work/life balance. If you have small children or other family obligations that limit your hours to the typical 9 to 5, this is not the company for you. That mindset is typical for Silicon Valley, however.