Pros
GEICO provides a good opportunity to start a career. The expectations are high and they won't let you lack, but that is a good thing since it requires you to learn to act professionally. GEICO has decent benefits. The profit sharing is a big plus. The company usually does very well thus profit sharing is usually very good. After a year you are able to move around the company to find a position that is better suited for you. Layoffs almost never happen. They just stop hiring if they feel they are overstaffed. You have to really do something wrong to get flat out fired. They will usually try to find a different position for you first.
Cons
It can be hard sometimes to break out of the basic positions at GEICO. Most work in sales, service, or claims. If you want to work for corporate, then it is much harder to find a position. The sales, service, and claims jobs top out over time and there isn't any way to continue moving up the ladder except to find a job with corporate (in underwriting, or IT, etc) unless you want to be a supervisor (not much benefit to this, just more of a headache). The work can become very monotinous.