Pros
Smart & young coworkers (all work is team-based), small firm, flat structure (quick access to senior management), impressive compensation, challenging work. Initiative is rewarded. Decent review process to get candid feedback on your skills. Management is interested in long-term health of the markets (not in plundering). Hours not insane and often flexible, work/life can be very good if you manage it well. Workplace politics/red tape non-existent.
Cons
Coaching/mentoring could be much better (has been improving at a glacial pace). Location could be better (suburb/exurb of DC). Most analysts are recruited straight of college and many have the usual complaints -- my boss doesn't care about me, it's impossible to get promoted, we work too hard, why don't they provide free lunch like Google... which can be annoying (look up Bridgewater, Och-Ziff or similar funds for the same complaints). While not strictly "up or out," the 5-year retention rate is low (like most finance jobs) and a portion of people leave after 2-3 years, sign on to similar jobs elsewhere that are lower pressure, and then find they're not any happier and wonder why they left DC Energy. Some others realize that finance is not for them and find something that does make them happy.