Ventajas
After six years, the best "pro" I can think of is leaving. The company tries to develop a "family" aspect with their employees, but if you do not have your "good ole boy" ticket punched, forget it!
Desventajas
Too many to list, but here is the biggest: The company management frowns upon (and often hinders) employee self-improvement. The expectation is for the employee to sit in his or her cubical and do his or her job. If the company wants the employee to advance, a manager will approach the employee about a new position. An employee asking about advancement or even (The horror!) bidding on a posted position is seen as being "upity." ("Who does he think he is applying for that posted job!?!?! We have so-and-so already earmarked for that position! Now we have to go through a costly and long-term interview process!") I even had negatives on my performance reviews because I applied on outside positions. And if by chance an employee actually succeeds in getting an offer for an advancing position, he or she can bet his or her manager will block the transfer. The only way I was able to advance from my position there was to leave the company.