Pros
A great line in the CV, opportunity to relocate to countries with strict visa policy, opportunity to work on a product used by billions, great culture, opportunity to learn from the very best software engineers, occasional difficult problems to solve, protective manner of the employer (like free food, gym, doctor, massage, washing machine and everything else in the office).
Google has a strong security team which really makes you feel safe even in the most dangerous situations.
Cons
The salary is average, it could be larger.