Pros
The total compensation package is generous, with opportunities for earning more through good, hard work. The caliber of colleagues is very high, sometimes daunting even. The company is very transparent - you can get a good look at what is going on with nearly any project, and senior management frequently communicate about the direction and goals for the company. There are an amazing number of really interesting projects to get involved with, and lots of opportunities for education and professional development. Google has big values, big goals, and works to solve big problems. It is an exciting and rewarding place to be.
Cons
Google isn't for everyone. Google isn't just a big company, it is (or very recently was) the fastest growing company in history. That growth has created some strain. Some things haven't grown to match. A lot of the finely tuned machinery (effective and appropriate management, consistent methods, best practices) that keep large, modern companies running smoothly haven't had time to develop. Because of this, there is a great deal of variation across Google. Some areas are very much like the near-mythical stories weaved by the likes of Fast Company, and others are more stagnant. This is also mirrored in Google's products - some get a lot of love and others are left to dry up from disinterest. It is possible to do well and be happy at Google, but you a) have to take the initiative to make that happen and totally own it and b) recognize that Google is a big company with lots of people - there will be friction, politics, and things that drive you crazy.
