Vantaggi
Most individual contributor co-workers are awesome to work with. They are helpful and supportive when providing help, and are appreciative and gracious when you help them.
Svantaggi
There is a definite "old boys club" here. Only a privileged few get training or recognition, as there is a strong caste system in place. If you're not a suck up, you're treated like a cancer. Dare not present an opinion that is contrary to your manager's. It it's not his (or one of his pet's) idea, then it's a bad idea.
I thought things might get better with the acquisition by HP, but I was sorely disappointed. There is no investment in the employee, betraying a total disregard for the employee. The individual contributor is just another nameless part number that can be discarded replaced at will by management.