After several years, I left Aon feeling very disappointed with my experience. It began with lots of promise and excitement, only to realize my career was growing stale with no where to go for new opportunities.
I've seen reviews from employees saying there are options to move around. I didn't find this to be the case, and it has been acknowledged by senior leaders that Aon needs to greatly improve in this area if they want to hold on to talent.
Depending on what group you're in, Aon can be boring, where everyday feels the same. My experience with management was good, but I didn't feel they were truly interested in helping me advance my career, despite being given positive feedback about my performance regularly. If you're not in the "inner circle" you'll be easily forgotten about and the high visibility, career advancing assignments will rarely get around to you.
Now that I'm with a new company, my eyes have been opened to what a truly great culture feels like and what Aon lacks to be a top notch employer.
Many recent reviews have highly rated Aon, but I suspect this will change once the layoffs begin from the Willis Towers Watson merger.