Pros
The prestige of being with a company that is still out on the cutting edge, someplace that while fresh and exciting also has stability as a company. It may not be like the Wild Wild West days of the Valley at Apple, but it has moved into middle age more gracefully than some other companies have. They've done a good job of not throwing out all the perks as they aim for profitability, and the management team over the last decade seems not to have put a foot wrong in some time - if nothing else, the stock performance alone vouches for the the choices made.
Cons
The biggest problem comes if you're not in a group that is contributing directly to current projects. If you don't have the visibility, if your group is in some more pedestrian area like support or fulfillment, you won't get your share of resources or headcount. If you're not located on the Loop, and you're not turning out new product, be prepared to be an afterthought in the mind of the company at large. It's also extraordinarily difficult to move around within the organization; it almost seems easier to leave and come back than to apply internally for new positions in other groups.