Pros: The office is decent, and compensation for a first internship is competitive compared to other companies. It's a good place to launch your career, but I would not stay here long-term.
Cons: Note: This is speaking from personal experience only.
I was on a QA team as an intern. I honestly did not have the chance to learn a lot during my time at IBM. The tasks given were trivial, and the internship was definitely not the best use of my time as a student.
Even when I asked for work, the tasks were still not things that would ever benefit me long-term. I've worked at some other companies after IBM, and the others expect and give you work that almost makes you equivalent to a full-time team member.
At IBM, many peers and I were questioning why we were even getting paid at times, and we often felt neglected by our managers and team leaders. I've never experienced this at subsequent companies.
After my time at IBM, I heard a lot of peers at different schools talking about how a lot of interns "sit around" and "do nothing" while at IBM, and unfortunately, I saw and heard a lot of this while I was working there. Again, this reflects my personal experience and the experiences of many of my peers. However, I do know several interns who also found the experience to be very valuable.