Pros
Overall, I had a great experience at 300Brand. I say that because you work cross functionally around each of their individual companies. I knew nothing about federal IT before I joined, and it was interesting at times. The starting pay for entry level is ok. For the DC area, it's not the best. However, if you're decent at your job, you can move up quickly. My coworkers were amazing, and jr staff get along very well. Additionally, the former HR tried to contribute to a fun company culture with themed events that inspired community. Benefits were also pretty good, especially healthcare/dental in the face of rising costs. They also tout the week off between Christmas and NYE, but that ain't special or unique.
Cons
That said, the CEO is troublesome. A true narcissist with bad communication skills...at a PR company. Examples not limited to: announcing an individual employee will recieve a bonus at an all company meeting and citing the exact dollar amount, mandating said meetings be an hour before opening - and employees are not to mark this as working time, having his own wife act as HR (because that's not a conflict of interest), mandating attendance to a 6+ hour event (again, not paid or given time off), changing employee roles on a whim...it goes on It also seems to me that one branch of the company is favored over another. Everyone call tell, and it's terrible for morale.