Pros
Colleagues are absolutely brilliant. KIPP teachers, in my experience, are immensely talented in education philosophy and practice. The people that you work with will save your soul. Classroom resources are readily available and able to be ordered. The salary is relatively competitive especially for novice teachers.
Cons
You work more than an investment banker for a fraction of their pay. School leadership does not care one iota about your career trajectory, especially if you are a successful classroom teacher. If you are producing results on assessments- their interest is to keep you as a cog in a wheel. Then, use your data to support their failed leadership strategies. If you have a legitimate concern about a workplace problem- HR will just say that "principals have freedom to lead". Professional development opportunities are few and far between. Salary scale is a complete and utter mystery. If you call off- be prepared to be interrogated via text, email, and phone- just short of a good ol' fashion waterboarding.