Pros
The two things I loved the most while working at Czero were the projects and the people. The projects felt impactful (mostly clean energy/clean tech), and were always super interesting and technically challenging. I never got bored because there was always something new to learn, and management was receptive to feedback about what skills I wanted to learn, or types of projects I wanted to work on. It's a close-knit team with a positive work environment. Everyone is very respectful of each other and ideas and values collaboration and team work.
Cons
The only cons are ones related to the inherent nature of consulting rather than Czero as a company. There were inevitably times with urgent deadlines, and some slow times in between. Also it was sometimes disappointing to get really invested in a project's success, but not get to hear about it after the customer's project with Czero ended.