Ventajas
The company is not going anywhere. Easy to get the required resources to do your work, if you are working in an important enough arena. Company reputation is quite good. Name recognition is also good. Generally the level of professionalism is wonderful. Non-union advancement and pay increases make sense and are mostly fair. Movement within the company is encouraged. Starting to more liberally embrace telecommuting and work from home. Great work life balance. Good tuition reimbursement 15k/yr for MS. Many locations throughout the country and world. Even if your program gets cut, if your are a good employee they can and will find you a position. Given upcoming percentage of retiring employees (~50% in the next 10 years are at retirement age) career advancement opportunity is very high.
Desventajas
Cumbersome routines and traditions. Lots of older employees quite set in their ways. Union tech positions are set up for the average performer as a lifelong job, far too stagnant. Tech pay is lower than other companies for the same type of work. General resistance to the value that open source technology can bring to the table. Percentage of truly incompetent workers that get shuffled or promoted away from their continual failures.