Pros
Interesting work environment, good benefits, good pay, one of the bigger news and financial power houses in NY. If you need to build a resume, Bloomberg will do very good on your resume. If you have the right attitude and perseverance, you can move around and succeed at Bloomberg. However, mind the politics (see cons too) Also, for US standards, Bloomberg offers a generous vacation package (4 weeks), and they will be very loyal and generous to their employees (provided you don't f them over). If you have any personal issues or need time for personal reasons, they are very forthcoming and easy in making arrangements.
Cons
There are 2 potential downsides at Bloomberg that (if you are lucky and/or skilled enough) you should dearly avoid: inter company and interdepartmental politics and power-plays, and bureaucracy. There are a number of managers who earned and build their little power empires in the last 2 decades, and who are clinging on to both their power and their old ways. Avoid these trolls of the 90s at all costs! While Bloomberg is very loyal to its employees, the downside is that these 'bad' managers and their little power tribes are not removed as they should be. THEY ARE PARASITES. If you are skilled and smart, you will learn how to avoid the bad manager vortex. The 2nd down is the occasional suffocating bureaucracy. Annual planning and budgeting is not unlike a 3 month ongoing water-boarding experience that has killed many a great business idea. JUST SAY NO to any such bureaucracy! (trust me, you';ll be fine refusing to participate, secretly most management HATES the process, and they'll silently will approve your insubordination) Also, the snacks are really not that great. Yes, you get free sodas and coffee, but forget about the snacks, they are horrible....