Pros
Can be a great place for those with an analytical bent depending on team placement. Business issues are addressed with analytical rigor and people are interested in finding the best answers. Some of the teams have a friendly and fun atmosphere - lots of young people who often hang out together when they are not at work. There is some focus on developing general business skills so people are able to take some of what they learn at Capital One and leverage that in other positions at other firms. There is certainly a good bit of talent - lots of smart people at all levels of the organization
Cons
There are significant downsides to starting a career in such a large organization - one that sometimes feels stagnant. Opportunities for advancement are often based on matters of luck / building visibility rather than in delivering strong results. There are significant organizational hurdles to getting sometimes simple things done - detailed prioritization processes and so on. Success in navigating those channels can play too large a role in overall success. It's hard to get aware from the fact that much of the business feels dirty - or at least ethically questionable... getting people who aren't smart about credit to pay all kinds of fees doesn't give you that warm feeling at night.