Very bad experience
No proper salary, no proper process for promotion. You need to make sure you have good terms with managers if you need to change your department, HR does not care what you feel working in company.
They will never ever come to meet you to understand what are your views working at IBM.
Many top performers have left IBM due to less salary I mean performers with 1, 2+ ratings. I know becos I bolded 2+ rating and got 300 bonus and no salary hike.
Iam a current employee of IBM while writing this and praying that I get a nice offer after 3 years of experience and will make sure that in near future ibm will never be in my list of companies for whom I would work ever.