Pros
If you're young and need a year or two of experience, this is a great place. They'll hire almost anyone, chew you up, burn you out, and lay you off. IBM notoriously pays lower than others, so you'll have an opportunity to boost your salary as soon as you leave. The benefits used to offset the low salary, but they have been whittled down to average, at best.
Cons
No raises, No education, Too much travel, high utilization targets. For example, while IBM is making record profits, a blanket decision was made not to give I/T Specialists raises. Doesn't matter what you did, no raise, no chance. 110% utilization makes you average, (rated a 2) which means no raise, no bonus) Plan to work 50 hours minimum to keep your job, 80 hours to excel, and that is only if the contract allows for it. (FYI, travel time doesn't count).