Pros
The benefits and care of employees is obviously world class, and compensation is almost unmatchable. But the company attracts some of the best talent and best people to work with in the world, which is the most important bit. Potential impact is always huge, and it's great to wake up in the morning and hear that the company you work for is going to try and defeat death, or bring internet in balloons to rural areas.
Cons
Google has gotten really large, and depending on where you are in the company, some bureaucracy and politics can get in the way. The company is very conscious of it, though, so it's less than you might see at other companies of this size. Launching is also the main emphasis -- it's hard to hire some of the brightest people in the world and ask them to just maintain some code base. Almost everyone is very entrepreneurial and always want to be working on new things, so maintaining things and following through of things can sometimes be difficult.
