Pros
More direct contact with senior management. Wal-Mart has a flatter organizational hierarchy comared to most companies. Along with that, the entire home office is located in one geographical area (Bentonville). This allows more contact with directors and senior management. If you're a hard worker, regardless of educational background, you could find vast opportunities to move up the corporate ladder.
Cons
Wal-Mart has a minimum 45 hour work week, but most employees would consider themselves lucky to only work that many hours a week due their enormous work load. There is a cult-like atmosphere which may make some people feel a bit uncomfortable. This involves meetings that start off with the Wal-Mart cheer. As everyone has probably heard, Wal-Mart has relatively poor benefits. Wal-Mart always seems to be in some sort of controversy whether deserved or not.