Pros
Mercer is a huge company, with several different business units and offices in many different cities. I can speak only for the Talent business, which was where I worked. Mercer is owned by Marsh & McLennan Companies (MMC). I was with a group that previously had been with another MMC consulting company. MMC moved us to Mercer to strengthen Mercer's capabilities in our area of expertise. My time with Mercer (about two years) does not reflect my much longer time with the group I was in. Our new colleagues welcomed us with open arms. They were very friendly and helpful and didn't silo information from us. I can't say enough good things about the people I met there. Those who found their niches at Mercer often retired after 20, 25, or even 30 years, which is rare in this day and age. With the exception of what I put in the Cons section (which applies only to top management), the culture was among the best I've ever experienced. People treated one another with respect, and they went out of their ways to help one another. Siloing information and having an attitude of "It's not my job" didn't get you far. I was never micromanaged. Work/life balance (for non-consultants), health insurance, and other benefits were very good. Overall, I recommend Mercer as a place to work, as long as you are aware of and okay with the Cons.
Cons
Most of the Mercer business units were doing well financially. Unfortunately, my group was part of one of the few businesses that weren't doing well. This led to frequent reorganizations and reductions in force. New initiatives weren't given a chance to succeed. If a new initiative didn't prove successful within a couple of quarters, someone else would be put in charge of the function, and that someone would come up with a new initiative. Mercer Talent stresses to clients the value of finding and retaining good people, and that training new employees is expensive. The group I was with, having come from another MMC company, never quite fit with Mercer's processes and organizational structure, and we were eliminated in 2014. There were other open positions within Mercer for which some of us were qualified, but those positions were put on hold at the time of the downsizing. There was a feeling among many of our colleagues in areas that weren't downsized that management could have and should have found other opportunities for many of those who lost their jobs, especially loyal employees who had been with the group for many years and had valuable skills and knowledge. In some (not all) job categories, pay was low, and opportunities for advancement were limited or nonexistent. In general, people in the earlier stages of their careers stayed long enough to get some experience and then moved on to other companies. Those who were further along in their careers and who thought they were fairly paid stayed for many years. I was among the satisfied employees and would have been happy to stay indefinitely, as long as my areas of responsibility continued to grow and change. The level of bureaucracy could be annoying for those of us who had come from smaller companies. "Once size fits all" policies, while efficient, often serve only a portion of employees effectively. All of this goes hand in hand with a huge company, though