Pros
HISD is a monster of a school district. It provides opportunities in many different educational settings, such as charter schools, magnet schools, and regular public schools. Once you're in, it's easy to move around if a particular campus is not to your liking. For the most part, the other teachers are helpful and down-to-earth. This, of course, varies from campus to campus.
Cons
HISD is a monster of a school district. Yes, this is a pro, but mostly a con. The district is too entranced in accountability measures and meeting adequate yearly progress benchmarks. All the students end up doing is testing. All the teachers end up doing is teaching how to take a particular test or analyzing data based on performances on tests. To add insult to injury, mandates are pushed down at will, and teachers are left to implement new changes to improve performance without adequate support, resources, training, or (most importantly) time. Teachers and support staff are asked to do the impossible while given few means of achieving those goals. It makes for a very stressful and frustrating work environment. All that... without even considering the type of student population you may be faced with... That's an entirely different story.