Pros
The company has been growing at a good pace for a long time and is continuing to grow. This means lots of opportunities for promotion from within--most of the directors actually started at entry level at EM themselves. The skills that people build are really useful, too. The alumni network is full of people who excelled at EM and now excel in key roles for Fortune 500 companies. There can be a fear of being "niche," but the fact is that expertise gets narrow very quickly even within large organizations. At a Big 4 or similar firm, you either are just a cog in a machine as junior staff, or you get very niche as you advance. At EM, it works differently. At <200 people, you can make a difference on day 1, then have your role and expertise broaden as you advance.
Cons
Consulting is hard work, and getting to world-class client outcomes is not always easy or convenient. EM doesn't have the 80-110 hour weeks you see in other industries, by any stretch. But it's also not 40-hour corporate. A goal at EM is for employees to get to a level of skill and polish within 5-6 years that would take 8-10 years at a larger firm. This means seniors invest in you and give you opportunities, but naturally that means pushing beyond your comfort zone frequently with new skills and responsibilities.