Pros
Google is famous for good reason. The culture is terrific, the perks are great, and the rewards are meritocratic, which is great because your peers are fabulous. You will never meet people smarter and more dedicated than Google colleagues.Plus, depending on your division and interest you really do have opportunity to solve interesting problems.
Cons
When I started at Google in 2007, it was a much smaller company. By the time I left in 2014, it started to feel a lot more big-company-ish, with more bureaucracy and politics. They did a good job of trying to combat that as best they could but at some point the reality is just that they are huge. This isn't necessarily a bad thing, if you like working in big companies, but I was seeking something smaller and more mellow.