Pros
Work life balance is fantastic; you get to work with some great people. The ability to obtain certifications is available and for the most part encouraged. I had the ability to work in three different departments within 2 years, so transferring is not a problem if you are a competent employee.
Cons
Pay is far below industry average (I received a 30% increase when I transferred firms). It is a true hierarchical business. Managers report to managers who report to managers that report to other managers. That being said higher level managers tend not to listen to those that work on site with the client, instead listen to managers based out of the home office. To date I still cannot believe how many "team meetings" we had which was amazing considering all of GTSI is smaller than the project I am on now.