Pros
Perficient gives you the tools to do your job. In my experience, management is attentive, available, and enthusiastic, not just about the company's success, but each employees success. We were acquired by Perficient, and that's always a tough time. But everyone at Perficient, from the senior folks down to my new counterparts and colleagues made me feel welcome, and went the extra mile to ensure the process was as seamless and painless as it could be. And I most certainly appreciated that.
Cons
Zip. I was afraid becoming part of a significantly larger organization meant that there would be material changes to the way we conduct business, but I have yet to encounter any negatives. I have worked at very large companies, and startups, and Perficient knows what they're doing in terms of maintaining an environment and culture conducive to its employees happiness.