The site I worked at (the all-boys school in Brooklyn) was very discipline heavy in terms of their approach to the kids. I found it difficult to balance learning their very specific system of point rewards and penalties while also getting to know the students. I didn't really ever feel like the classroom was mine because teachers had to follow the school-wide structure of lessons. You also need to make sure you really buy into the idea of silent hallways, a highly structured schedule with very little free time, and sometimes demoralizing penalties for indiscretions. I'm not going to say these policies don't work; they're just NOT for every student nor are they in accordance with some educators' teaching philosophies. I advise all teacher applicants to ask to spend a regular day in the school during the interview process so that you can see how your school site is run.
Long hours may be a con for many teachers, too. I personally didn't mind them because I've always worked long hours as a teacher; however, if I'd had kids at the time, I wouldn't have been so keen on staying at school till 10pm and getting there at 7am.
