Pros
Great company to start at with a decent salary and plenty of smart people. You will work for mainly big pharma and biotech clients. Starting salary is livable and okay, but, you will have to work at one of the CLIENT sites, not out of the ZS Evanston office. So, plan your commute and move accordingly.
Cons
As stated in the headline: bad office politics / gossipy culture. This is a small company and favoritism runs rampant. There is less of a focus on competency and more of a focus on tenure. The average promotion time between levels is ~2 years. People can be quite passive aggressive; know how to play political games, and most importantly: be a gray rock. ZSers are very competitive, don't let the company values fool you. When it comes to 'tenured' people (non-new hires who have been there for over a year): If you outperform somebody, tread carefully. If somebody messes up or throws you under the bus, you absolutely cannot flame them. Know how, when, and to whom to escalate project matters to This is a small culture that protects its cadre of favorites. If you are working with a favorite, take some hits to the chin and try to move off the project. Competence does not outweigh politics here to an extreme. At my previous place of employment, there were politics, but not this many 'implicit rules'. This is a lesson I've learned the hard way. Don't be me and you can succeed at ZS. Takeaway: given the toxic culture of favoritism and 2-year tenure, I recommend using your time at ZS for work experience gain to move onto a better place of employment with more unbiased reviews and more focus on results/competence.