Higher total compensation than competitors, engineering-dominated company, and incredibly bright coworkers.
Pros
Higher total compensation than competitors - competitive salaries are augmented by large cash bonuses, equity awards, 401k matching, commuter benefits, and incredible on-campus perks, such as free meals and massages, but also including so much more. Incredibly bright coworkers. Famous computer scientists from all over the world are working in small teams at Google and the average engineer is able to approach any one of them. Very thorough annual 360 degree feedback and promotion committees to decide promotions allow individuals to succeed even if there is a disagreement with their direct manager.
Cons
Google hires so aggressively that you don't necessarily get to meet your manager and team mates before you start. There are so many new people coming in each week that they literally can't arrange this. That is a big downside compared to other companies where you would meet your potential manager before agreeing to work there.