Pros
Capital One is full of very smart people from around the world. The recruitment process is quite intense and that insures a good pool of analysts that run the business i.e. business, data, operations and statistical analysts. The positions demand fairly high competency in math, programming, statistics and the mix depends on the job family. The work place is very relaxed and casual. However that does not mean that work is taken casually. No decision is made without grounding it in data and a lot of analysis. Taking time off for vacation/personal/family stuff is not a problem at all. You can work from home on days that you don't have meetings with senior leadership. I generally like to go to the office since that allows me to interact with people, but I stay home when I don't feel like getting out of bed. Work attire is casual (most people wear jeans). As long as you get you work done well you will be fine. You need to go above and beyond your present level to get promoted.
Cons
In my opinion, the legacy business (credit card) is still very dynamic, challenging and full of very bright and talented people. That business has always been very enterprising, almost like a start up, full of youth and vigor. Since capital one acquired 3 banks over the last 4 years, the bank side of the business came with a lot traditional banking type people. The two cultures are quite different but luckily if you are in card then you dont interact with bank at all. Capital One has tried to move some card folks into the bank to instill some of our traditional data driven strategies and ways of doing work into the old-school bank. That has been full of challenges and I've heard a lot of horror stories from people who moved there. Basically you add 20 odd years to the average of a card employee and you get the average age of bank employee and you can imagine the problems the generation gap can bring. Capital One doesn't pay as well as other financial services companies. I guess one reason it did so well in this past recession is that it gives moderate bonuses. however money can only do so much for you. The work life balance you get working for Capital One negates the lower pay. I think I've been spoiled working for them...can't imagine to leave. Wait, this was supposed to be "Cons" part. Oh well!