Pros
Company is extremely reputable in the DC area and works on many high profile projects. You definitely get to wear many hats when working onsite and pick up many valuable skills in the construction and project management realm. Great training opportunities on a higher level... teaching about PM skills, RFIs, Budgeting, LEED. Many folks have been with Clark for the long haul so there is definitely a lot of experienced people to learn from.
Cons
Despite all the "hats" you get to wear on projects, there's typically a negative attitude amongst the lower level staff as upper management treats them poorly. Countless times where a task would be presented as a "great opportunity" but in reality it was likely others just did not want to do a tedious task and wanted to make someone else do it. Also, mid/high level management would ask office engineers to perform tasks with little or no training and then get annoyed when asking for help. Promotion cycles are about 2-3 years so compared to a quicker pace company employees may not see the light at the end of the tunnel. Work/Life balance is horrible... onsite by 6:30/7 AM (which is typical of projects/non-issue) and then working 10 hours at a minimum but typically 12+. Depending on project status it's not uncommon for weekend work or late nights (upwards of 14 hours) if a project needs to meet crucial deadlines. Long days are fine, I knew what I was signing up for but there was always an attitude from others that your personal life didn't matter and any problems caused by others were somehow your fault. Anytime I took vacation days (only 10 per year) I would get attitude from colleagues. It's the nature of the business but still not something you want to see as a new hire starting your first job.