Pros
The majority of the people who have been there more than 7 years are the best thing about the company because they've lived through the largest period of corporate growth and are the most down-to-earth. The benefits are wonderful (now that they have a legit family leave policy) and there are many ways to integrate yourself quickly into the Bridgewater community (concerts, happy hours, plays, other outings). Standing desks are pretty common and make for a more productive workplace, in my opinion. It's not uncommon to be walking down the hall and the CIO says 'good morning' and stops to have a chat. Extremely smart and interesting people.
Cons
Tough culture - be prepared to be reduced to your mistakes and weaknesses on a daily basis while maintaining a smile on your face. The 'principles' are sometimes used for evil and not good by managers with no people management skills (and even worse analytical skills). i.e., they're sometimes a fall-back formula for firing people. You will never be let 'off the hook' (which can be a good or bad thing) and no working day is ever easy. After too much time there (2+ years) and depending on your specialty/experience, your attractiveness to potential employers starts to wane because you become really good at working at Bridgewater and nowhere else. The company is becoming extremely bureaucratic compared to 5+ years ago but that's probably a natural outcome of growing so quickly. Things generally take longer than they should to get done unless you really shout and present a good case for what needs to get done.