Pros
The company pays well and they look to higher and promote from within. Many jobs at GDIT are based on military contracts so your milegage may vary depending on the specific contract details. As far as being a contractor goes, I have work for a few companies and GDIT is without a doubt the best.
Cons
They promise educational benefits then you (likely) will be told there is not enough money in the budget to provide any assistance with college tuition, certification, or educational materials. Insurance benefits are costly. The lowest deductible for insurance is $3000 which means that you have to pay $3000 out of pocket before ANYTHING is covered. As long as you don't mind paying full price for most of the year it's not too bad. Company should offer more training opportunites.