Culture is pretty good, There a lot of smart people at Capital One. People are usually happy. It's a good company if you're looking to settle down in an area
Cons
Stack Ranking. Absolutely sucks. Kills any incentive to help your peers which is sometimes detrimental to a team. People sometimes code stuff that only they can understand, and refuse to explain to others.
If you have a good manager you will have a pleasant experience with the company. If you don't then you won't. Thats about it.