Pros
$ - The money is good. The benefits are excellent. The perks are wonderful. The bonuses are large. The regular employees are awesome, and fun to work with.
Cons
Management is ineffective at best, and incompetent at worst. The entire company is very much a cult of personality. There is a massive "not invented here" complex. Managers that have risen through the ranks over the last few decades are very stodgy and outdated in their ideas about business and development best practices. I got negative performance reviews for mentoring others as the most senior developer on the team. Management did not understand the problem space at all - web development - and this made it very difficult to have non-stressful conversations with them. Some teams at Bloomberg are better than others, mine was generally recognized as the worst. The entire team went to senior management with complaints about the problems with out direct manager, but nothing was ever done.