Pros
The breath of experience at a large firm like Aon should not be under valued. You can learn a lot from working in a shop like Aon. The volume and complexity of the deals you will see is great and will broaden your experience. You will learn more in a year here, than you will in three or four years at a smaller brokerage purely based on volume. They also have good training, they do at least try to work on getting people trained and ready to do their jobs, it can be hard given the volume of work but you get what you put into it. The only reason I would recommend working here is to get yourself some experience, learn as much as you can and then use that knowledge to find a better long-term position elsewhere.
Cons
Nearly the entire leadership of the company is run by former McKinsey partners on down the line. The issue with this is the management is more concerned with chasing a quarterly revenue goal than they are with building long-term sustainable growth. How can you have a department that is growing by 35% year over year and not increase their manpower? You end up working the people you have to death and it creates an atmosphere and environment where you are required to be working at home and on the weekends. This isn't management consulting and we shouldn't be trying to turn Aon into a management consulting firm. People will work hard, but to expect them to choose between their families and their job is going too far in your quest to chase a quarterly revenue and stock price. Then to make matters worse, even though the group does well but because other groups in the division did not, only a few people get bonuses. So on top of working everyone to death, they get less than 2% raises and half of them get no bonus.