HBO used to be a great place to work - they took calculated risks, encouraged creativity, and had a streamlined approval process. Now is not the time to work there until they fix their culture. It is toxic to the core, and until they address those issues on a cultural level I can't advise strongly enough not to work there. Incredibly political - which starts at the top.
No room for upward movement, very political, and Time Warner is merging with AT&T which presents an uncertain future.