Pros
A large company with lots going on. While declining, there are many very good people who work at all levels of the company, and some chance for movement. I say some, because its superficial. The technology available to work with and implement is cutting edge, and access to resources is second to none. But all that is on the decline.
Cons
The company has become disjointed. Many layers of non functional and micromanaging middle tiers that provide no value to customers. Customers have stopped being the focus of the company, while arbitrary directives are now the way of life. Solid and progressive management who focused on what was important - our customers and our quality of service delivery have quit and moved on. This leaves CDW with a branch of business that they have no idea how to properly execute. They are aggressively trying to short change service delivery, and turn it into just cost center to support their licensing goals. Not being a nimble company by any means, the downturn in the economy have caused benefits to be stripped to the bone (no 401K matching, the re-defining of bonuses, etc...). And the oppressive pressure from up above has translated to highly skilled and well paid employees being micromanaged and baby sat by people who have no interest in keeping a workforce productive and happy, but just demanding some arbitrary % on a report.