Pros
Well, it's Google:) You get exceptional perks, including subsidized massages and gourmet food. The average intelligence level of employees is very high and most of the technologies you work on are bleeding edge. The company tries to maintain open information culture and keep people aware of what is going on.
Cons
I've joined in 2005 and Google in 2005, Google in 2008 and Google in 2013 are 3 different companies. The early years made Google the icon for IT world and it was respectfully so. However as the company grew the engineer-centric and open culture has began to disarray and the people (mostly in mid-to-senior management) that should have never been hired started to erode this culture. Now it is becoming more and more like other big corporations. It is still a great company to work for and far better that most of what is out there, but comparing to what it could have become...