Pros
Benefits are good, but relatively poor salary. Essentially, golden hand cuffs for many due to long-term profit sharing plan. Some really nice people. Free snacks.
Cons
In my subjective opinion, very aggressive business culture regarding both employees and clients/stakeholders. This made me feel depressed for a long time, even after leaving Bloomberg, as I couldn't ever accept their business culture and values. It was demoralizing to see how employees were treated as a commodity -- employee turnover was very high and people just didn't stay. Very low organizational structure meant that there was very little career upside. To my mind, Bloomberg's HR practices were aggressive and questionable as well. Just as an example, they did not allow their employees to organize a labor union, although this right is separately addressed in the UN's Human Rights Declaration.