Pros
Structured training for a smaller firm - globalized and coordinated training and development means technical and soft skills are actively trained rather than expected to be apprenticed. Pretty flexible - office changes, either international or no-travel projects, MBA planning.. all requests are individually considered and managers genuinely seem do their best to help. Kind of well known in consulting and selected industry circles these days (at last!)
Cons
Note ZS is NOT a strategy consulting shop - its all operational stuff, be prepared to look at and process data for your first year or two. Main drawback I found was industry specificity. If you have had enough of Pharma (many people have after a few years), its time to leave. And where do people go when they leave? Almost always people leave to end up in mid-management in pharma co's.. only a few lucky ones will move upwards to the McKinseys or BCGs Additionally the recent management, especially in the European offices but also in the US, is held in far lower esteem than was the case a few years ago. Growth has stalled, business is slowing. When applying to MBA schools, ZS seems to have a mid-perception among the top schools. Many people leaving into MBA get into top-10 schools, though the company's brand wont stand up enough for a top-3 school (very few zs-ers go to HBS/SGSB etc).