Pros
For a young person or someone new to IT IBM still looks good on a resume. Working there for a few years will allow someone to get basic skills and experience that will be helpful after leaving IBM. IBM has fairly decent benefits in regards to Medical and Dental insurance, flexible working arrangements and 401K. The flexible work arrangements make for a reasonable place for a retiree to work as a supplemental employee. There is also a lot less pressure as a supplemental employee and pay is typically better than being hired as an IBM contractor.
Cons
IBM's intent is to offshore many jobs in the US. This results in high performing employees, in addition to lower performers, being laid off to move much of the highly technical work oversees. IBM used to provide a lot of training for employees in order to maintain current skills and allow folks to upgrade into new technologies. Over that past several years education has been curtailed to increase earnings per share in a decreasing revenue environment. Few and far between pay raises/promotions for expected work load. When I first started with IBM management and executives were engaged with employees. Under the current CEO management has become isolated from employees. The result is a work force that has no general direction or input into product/development cycles. It also displays itself in lack of innovation in products as the folks in the trenches no longer have input in the design processes. To sum it up I have told my children to look at IBM as an employer of last resort.