Pros
It's a big company that has lots of diversity, exceptional staff, and a long history of reinventing itself despite bouts with failed leadership. Historically, benefits were good and stated company "values" are focused on "win-win" philosophies. Work-life balance was reasonable, and employees felt valued. In some parts of the company, shreds of this history remain. If you find the "right" group / division (likely in a low-wage or developing country), there's still hope of a bright future and a potentially rewarding career.
Kontras
With the second consecutive CEO who lacks the ability to communicate coherent vision and direction to his/her employees, (aside from the relentless drive toward $20 EPS in 2015 which should be a byproduct of stellar performance, not a business target) the company has once again lost its way. Layoffs of high-knowledge employees and inward-looking short-sighted policies rule the day. Customer service has deteriorated as a result, and IBM's published sales numbers clearly paint the picture of the current trajectory. Fear and stifling control are the bureaucratic tools-du-jour, with hollow strategies and PR-generating "partnerships" rounding out the equation. IBM's nimbler and more customer-focused competitors are once again eating its lunch technologically, commercially, and service-wise.