Pros
It really is a great place to work. TCG has won a number of DC area and National 'best place to work' awards. Lots of flexibility in most positions. If it's possible to telecommute, and you want to do it, TCG is very encouraging. Reasonable computer/internet expenses are reimbursed for a home office. Company policy and things like the time reporting system are geared to a flexible schedule. (ex. telecommuters can take 8 hours for a national holiday any time in the month if they would prefer to work on the actual holiday and take off another day.) Company actually implements their core values. Two important ones for me are "collaborative" and "fair, honest, and open". Just about everyone I work with matches those descriptions really well. Lots of smart people to work with. (also a core value) Not just the tech people either. The back office, business, customer facing folks, everyone. A lot of really odd perks you don't see at other companies. Too many to really put down, but here are some of the good/unusual ones: free tickets for employees to local events. Everything from theater to DC Capitols games. Company subsidized mountain vacation home. $1000+ a month for to employee run events that anyone in the company can suggest if they are willing to organize it.
Cons
TCG is a contracting company so we don't have an product we build/sell. Most of our customers are great. Even so, you are still a contractor and sometimes a client will make odd decisions that you have to live with. Some projects don't have a real customer site and require telecommuting. If you aren't into working from home, find out how your project team will be setup.