"jackson is IR and Global Affairs focused, interdisciplinary to all background and jackson has better funding. IDE is development, more technical and requires pre econ knowledge, narrower syllabus."
Jackson is much more flexible than IDE and allows you to blend business school, law school, global affairs, econ, anthropology, etc classes to tailor your schedule to your interests. You can also really get to know senior fellows, whereas IDE doesn't really have anything analogous. Also, you can take IDE courses as a Jackson student.
IDE students tend to be younger, almost all are international students, and were mostly econ undergraduate majors. Take a look at the Jackson student bios and IDE student bios (both are on our websites) to get a sense of the difference.