Pros
I worked in the Dallas office, so I can only speak on behalf of that particular region. GEICO is a successful company, I'm sure you've seen the commercials on TV, heard them on the radio, and if you're reading reviews about it you'll probably start seeing ads pop up in your web browser. GEICO provides really good benefits to its associates, some of them were about as comparable for a civilian job to what I got in the military. The thing I always enjoyed was that the supervisors and management team were always willing to provide help and didn't make you feel like you were bothering them if you had a question. They also do quite a bit to acknowledge accomplishments both individually and as a team. Right as I left the company, the Dallas office did a massive shift realignment to ease some of the workload and make supervisors more available to their respective teams, which I'm sure has had good results.
Kontras
I don't know if you can really consider this to be a con, but it's definitely something to keep in mind if you're considering working at GEICO: They have extremely high expectations of their associates. The job I did in CSR is a call center job and you are expected to be available at pretty much all times to answer incoming calls. They seem to have no understanding or tolerance of taking time between calls to finish up what you are working on. You are there to be a worker bee, and that is it. They are going to try to squeeze every ounce of work out of you that they can. Basically, efficiency matters above all else to them. Also, it is sometimes very difficult to get time off. Even if you try to plan 3 or 4 months out, it is sometimes impossible. I know that you can't always expect to get the time off that you want, but in an office with as many people as there are, it shouldn't be that hard.