Pros
You work with very bright people and you learn a lot. If you just graduated from college IBM is fantastic since they're used to the learning curve, also there are many areas where you can become and expert.
Cons
A couple years ago IBM had very competitive salaries but now that Oracle and other companies arrived you can see that the salaries are not good at all. IBM has a 'brilliant' policy to give better salaries to new employees than keeping their current excellent employees with a good salary. Home office is forbidden for employees but you can see management has no issue skipping several days to work some place else, many managers are too busy on their careers that they don't have time for their employees. IBM Mexico has a full control on your salary and your manager has the full decision, in other words only the ones that keep sweet talking the manager will get a 'decent' salary. Promotions aren't always a great idea, I know a couple people who got promoted and their salaries increase was 0, literally 0. When I joined IBM I was proud, happy and I was able to see myself prosper for the following 25 years making the world a better place, nowadays I'm preparing to open my own company or join a more challenging and understanding company. IBM needs to focus more on their employees and cut the bureaucracy and old politics that make them a hard place to work.