Vantaggi
The pay's good for senior talent. The benefits are decent.
Svantaggi
Bloated bureaucracy and overbearing processes. Much lip-service paid to Open Source, but legal approval processes to be able to use it make it agonizing and slow to actually get permission to use it. Patronizing and often downright mean management. Management which often explicitly stifles and punishes any hints of dissent; aka, "honest opinions". Much arrogance about being "cutting edge", whereas the reality is that IBM is too slow to adopt new technologies. Co-option of terms like "agile", applying them to whatever IBM currently does rather than actually changing and "walking the walk". Constant fear of being on the "wrong" project or working for the "wrong" manager, which may lead you vulnerable to the next round of layoffs. A performance review process which often bears little relationship to reality, with only managers and a few "architects" giving any input into your review, as opposed to your actual peers with whom you work. Lack of money to buy equipment, resulting in obsolete computers on desktops, and a constant struggle to find adequate hardware to test on.