Pros
IBM issues laptops to all of their employees and depending on your manager this makes working remotely fairly easy to do. When it comes to HR related tasks IBM seems to trust their employees and their managers as vacation/sick time is not centrally tracked.
Cons
IBM is an extremely large company and as such sometimes suffers from its size. Because of its large size the company has implemented many process/requirements that cause inefficiencies in day to day work. Compensation and pay are awarded based on a pool system that is sub-divided as you move down the organization which results in limited flexibility for managers to reward top performing employees. Additionally as the company is spread across the globe you may be working with people who you've never met face to face for years.