Pros
A lot of very clever and helpful people work for this company, and generally they're all willing to help out and very approachable. Overall the benefits package is quite good, and annually employees can elect to buy or sell vacation, and define contributions to things like childcare vouchers, all manner of insurance products and one or two other things. There are also externally run schemes that offer further discounts in myriad areas. Another good reason to work for IBM? "Nobody ever got tossed onto the maybe pile for having IBM on their CV".
Cons
The sheer level of bureaucracy is overwhelming, and on the rise. Immediate management have had almost all discretion removed and simply obey what "the corporation" demands. Career progression is often through a series of box ticking and being seen in the right places rather than objectively. Bonus and salary increases are governed by the all powerful and thoroughly pointless "Personal Business Commitments" process and associated review, however managers are being increasingly given targets and asked to award on a curve - thus a highly performing team's members are pitted against each other, and a low performing team's members are also pitted against each other. Once the dust settles, it is easy for the more lowly ranked members of a good team to be worse off than the one eyed man performer from the low performing team's Kingdom of the Blind.