Pros
Many of my friends from college work at Google and Facebook, and from my conversations I can honestly say that Apple values design more than any other tech company. Don't get me wrong, Google and Facebook (as well as a few other notable Silicon Valley corporations) have extremely high standards when it comes to design and user experience, but Apple takes it to a whole new level. They treat designers like royalty, and it shows in the products. As a software designer, I do feel highly valued at Apple. I do feel that I am doing great work. I do feel that I am more of an artist, a craftsman, than a developer. And I do feel that the long working hours pay off, not in cash but in the ability to look at the work I've done with my team and think to myself that this is what Picasso would use today. That's priceless. The 'climbing a ladder for prestigious positions' doesn't exist here because that's not what Apple stands for. The workers are here to design beautiful products together, and if everyone competes for meaningless position titles, the product quality worsens. That's why Apple doesn't really give a lot of freedom to move up.
Kontras
Working at Google and Facebook and Twitter is probably better financially, and it probably delivers a lot less stress. That's excellent if you plan on having a family and spending time with your kids. I do have trouble managing time because I usually work overtime four to five times a week. Of course, this gets frustrating, but I love what I do, and so the extra work is never a reason to quit or complain. Secrecy is also a pain, as some of us even carry a wallet with half a dozen security badges. We are told multiple times a day that our work can never be discussed outside certain rooms, and in some cases we don't even know what were working on. For example, I had a project for a product that I had no idea about. I assumed it was a new version of iPad, but it ended up being for the brand new iPad mini. And I knew it was for the iPad mini on the same day the world was introduced to iPad mini. Yeah, that level of secrecy can really get annoying. But it also keeps things interesting ...