Pros
As a consulting company, ICF's greatest asset is its people. Almost all of the junior staff and project managers I've had the chance to work with over the past few years were friendly, hard-working, and really dedicated to the doing good in the world. I got the opportunity to work with a really talented team with tons of technical expertise to do work of a more academic nature at times. Flex-time and the ability to work remotely is great and there's the opportunity to somewhat customize your schedule, as long as you put in at least 40 direct hours per week. Good place to start working after college to develop your resume or land for a mid-career change after you've gotten some outside experience.
Cons
Unfortunately, I think the people that run the company at the upper levels are completely out of touch. Communications to junior staff are often dishonest and can be condescending. Senior management likes to pretend that they consider staff feedback before making a major decision, but in reality, big changes (such as getting rid of sick time) were sprung on employees without any notice and the direct effects on staff were obfuscated. When it comes to issues that affect the day to day lives of employees, management is not interested in our feedback (see: eliminating compensation and benefits as a category on the employee feedback survey entirely rather than soliciting feedback). Despite the recent focus on direct hours billed, many managers do not have the ability to allocate work and plan ahead for employees effectively, leading to unbalanced schedules between staff and poor utilization of staff skills at times. It can be difficult to work across divisions despite qualifications and relevance of the work. Despite being competitive with other companies as recently as several years ago, management has decided to make some big changes to benefits in order to cut costs--it is easier to squeeze employees than change the underlying issues with the company. Sick time has been removed, the formerly-good health care benefits have been slashed to your choice of an HMO plan or a CDHP ("Don't get sick") plan, lots of pressure to work overtime.