Pros
Great reputation in pharma. If that is where your long-term interests are, there will be plenty of exit opportunities. Most managers really do care about the development of junior team members. Most of the people you work with are extremely intelligent and nice. Benefits not as good as MBB, but better than most other consulting companies. Senior leaders have been making all the right moves to grow the company. Recent emphasis on training and evaluating consultants and managers on managing the scope of projects.
Cons
Expectation that you focus on a narrow range of clients, practice areas, or a specific industry after a short time at the company. Depending on office, you may only ever have the opportunity to work with a few clients. ZS does not have a bench model. Model works great for market research and operations projects, but not traditional consulting projects. Work-life balance is impossible to maintain. You will burn out unless you are incredibly passionate about the work you do. Little strategy work. Many projects are "cookie-cutter" in nature. You won't feel like you are making a big impact on many projects.