Pros
They offer a decent salary. They offer decent -- but not outstanding-- benefits for full-time employees. At the time I worked there, there was lots of talk of moving the business model from butt-in-chairs contracting to project work, which is generally far more interesting and fulfilling. Some staff augmentation engagements can last multiple years.
Cons
The opportunities for project work are a tiny fraction of what the company has to offer employees -- over 90% of the work is "staff augmentation" (butts in chairs). If you don't want to be paid to be a butt in a chair, you should look elsewhere. Opportunities for company-paid training do not exist -- you're expected to stay current on your own money. Often requested (required) to put additional hours on the job without billing on the timesheet, to make up for operational emergencies.