Pros
I believe that Google makes the world better, by pushing the boundaries of technology and making information more accessible. I'm constantly inspired by the things that Google does. As an employee I have excellent benefits, compensation and work environment. Colleagues and management are generally positive and supportive. Plenty of opportunity for growth if you are driven, otherwise it's not hard to "coast" either.
Cons
Because the company is big, both the technology and politics can get messy. There are many overlapping teams and products. Individuals and managers are incentivized to create new products/teams instead of contributing to existing ones. This results in products/features that overlap excessively. It also results in software that is excessively complex, as instead of building a single library we build multiple libraries owned by multiple teams.