Pros
IBM is a company that has excellent values. If ethics mean something to you then working for IBM should be at the top of your list. I have been with IBM most of my career and that's for good reason. Strong values and respect for the individual. IBM is so vast that you can really do whatever you want. I started my career in an administrative role, moved to finance then project management and finally pivoted into software development and management. If you have the capability and drive to learn new things then you have a company with endless opportunities. Working conditions are very good and both on premise and remote work are available.
Cons
The company has been struggling to grow revenue the past decade or so which has resulted in resource actions and expense reduction.