Pros
Being able to name an employer that absolutely everyone has heard of is nice, especially after having worked for small firms. The international culture in interesting, and exposes employees to a global set of contacts and resources. There is clearly a collaborative approach, and from the start my views were taken seriously, even while I was learning "the IBM way."
Cons
Everyone works remotely. Every project involves an offering team of at least 20 individuals, most of whom are scattered over several US and international locations. The IBM acronym now means "I'm By Myself" for quite a large number of US-based employees; I worked from my home office for two years, which was great at first. But the isolation, coupled with long hours spent listening to phone conf calls, got a bit tiring. It took more than nine months before travel budget was approved that let me visit the office where my new manager worked; and there was no flight involved, just reimbursement for gas and an overnight motel stay. This was frustrating, particularly as the company was producing very good financial results.