Experience is highly team/project dependant
Pros
First off, you get to work on problems at huge scale. Even the simplest issues can become remarkably thorny and non-trivial at such scale. Second, Google has arguably one of the best developer tools in the industry. It helps you be many times more efficient than the average. Third, Google's hiring bar is very high; so your co-workers are often brilliant, and you are seldom slowed down by dependencies on other engineers/teams.
Cons
Google is large, and so each Product Area / Product / Team have their own sub-culture. You might fit well in some, and be a miserable in others. There really is no good way to tell. Having brilliant co-workers is a double-edged sword. This also implies a lot of competition for interesting projects, and the bar for getting a promotion is so high that it is not uncommon for people to get promoted for over 5 years or more.
