An increasingly frustrating experience working for a Company where bureaucratic form has triumphed over function.
Pros
The people at Aon were alternately fantastic and horrible. Within your organization they would be great at pitching in and getting the job done. Unfortunately, people usually had to because of the lean (aka inadequate) staffing and resources allocated to get a job done. Consequently the best and brightest tend to come to Aon to learn the trade before leaving. It's the kind of Company where you come to learn before leaving to get rich elsewhere.
Cons
As a result of having too few hands and too few resources to get things done in a timely fashion the stress was, at times, incredibly high. In my eight years at Aon I had eight horrible Decembers which really puts a damper on the Christmas season. The other downside is Aon's refusal to invest in its people. Compensation increases are mediocre at best and are only made grudgingly. If you get one decent raise don't expect another for 4 to 6 years. Benefits are also surprisingly bad given the size of the organization and the resources it can leverage in risk management and human resources consulting. Health premiums for high deductible plans with HSA's are north of $100 per pay cycle with deductibles over $4000 and out of pockets over $7000. My current employer, which is a fraction of Aon's size, offers a plan in the same "metal tier" with lower deductible and out of pocket at a cost of just $5 per pay cycle. The dental plan is likewise ridiculously expensive for what you get. There's also the bureaucracy that you have to contend with. It's almost impossible to get basic hardware like monitors or cables. In one instance it took three months to get the necessary approvals from three layers of management above the department layer in order to get a cable that converted serial input to USB (retail value, $15). If you're looking at Aon for the special programs or benefits, and any one of those involves approvals involving HR or management above your department, just give up (for instance, forget about tuition assistance, which if by some miracle you get will result in a 7 to 10 year commitment to the Company).