Pros
The benefits are good and the base pay is decent when taking the benefits into account. Other than that, there is not much. One of the few perks that I do enjoy and would surely miss is that they still have actual offices for the majority of the employees. In a world where everything is cubicle, it is nice to be able to just close a door for a bit to get away from office noise and be able to concentrate on work.
Cons
Most folks know the cons: a process for everything, everything is politicized, movement and career advancement is difficult, the predominant focus now is on offshoring and having to interface with a revolving door of folks overseas. I see the company deflating its US-based workforce over the next few years by not providing incentives to new/younger employees and letting the older, more established employees leave as their careers end naturally. Internally there are a lot of 0-5 years and a lot of 15-20+ year vets. It is the in-between the IBM has failed to focus on and will likely face a lot of issues because of this in 5 - 10 years time when the majority of the vets retire.