Pros
You are essentially paid by the order, so you can make a fairly good salary if you work hard. Also, there is usually some form of free food available in the cafeteria. There are a LOT of employees, many of whom are extremely talented and bright. The friends I made here are absolutely wonderful people.
Cons
The social atmosphere resembles that of senior year in high school. Every promotion opportunity is essentially a popularity contest and actual competence is given minimal consideration when promoting. Many people in management have absolutely no history or experience in management. To make matters worse, there is very little room for upward mobility. You might go up one or two positions, but that's it. It definitely isn't a place for long term growth. Face to face interaction is generally discouraged. Employees are instead encouraged to contact one another via instant message only, or to give good or bad feedback through their intranet system. Thus, actual human contact is kept to a bare minimum. I imagine this might be a pro for you if you are a true introvert? Every order you touch is graded, and if mistakes are made money is deducted from your paycheck. Productivity is also calculated (you must complete a set amount of orders per day). Failure to do so may eventually result in termination. Company bills itself as "innovative," but most process improvement suggestions from bright, experienced employees are discarded. The pay structure is unnecessarily complicated, with different tiers for each level of productivity and mistakes and how much each correlates to in terms of dollars. It makes for very unpredictable pay checks. The physical atmosphere is okay (cubicles), although the desks and chairs are notoriously uncomfortable (most people start seeing a chiropractor within six months of starting due to the poor ergonomics). Frequent seat changes, sometimes to high traffic areas where it is difficult to concentrate, or you may move to extremely cramped quarters. In 4 years, I changed seats almost a dozen times. Overall, to me it was eventually not worth the stress and lack of long-term development opportunities.