VERY clique-ish. If you don't get along with people on your team, it can be hard to fit in with the employee culture here. Outside of your team, people are not very friendly. That said, pretty chill place to work. If you are focused on your career and have goals, this may not be a deal-breaker for you. This goes for the Philly office only. Princeton may be different. The culture in the Philly office stems from the start-up mentality (EnergyPlus days). Princeton definitely is a bit more professional and corporate with more polish.
Business casual (jeans) everyday
They took away free vending machines