Pros
Great peers to work with for the most part. No accountability - this is also a downside, see below. I am lucky in that I love what I actually do for a living, and CDW let's me do it at a good (but not great) salary. But organizationally they/we are a mess. The upside is the company is still profitable and that allows the negatives to get buried.
Cons
There is no organization, no vision, no leadership. Management is almost completely reactionary, and often makes completely uninformed decisions and can't understand why things aren't done when and how they expect them to be. They are arrogant as an organization, though that has been tamed or humbled into them in the past few years. There is zero accountability for poor performance, especially at the management level. On the contrary, becoming a manager at CDW seems to be the key to job security. I've seen 1 manager fired in my several year tenure at CDW, and it was astounding to see the multitude of repeated mistakes that occurred before the eventual dismissal.