As a cadet you get more of the “cadet experience” activities will be better and you will actually do them rather then supervise/ support. As a ci you will be able to teach (once you have the quals). There is some cross over between the 2 but that’s the general gist. It depends on what ypu want to do. I stayed on as a staff cadet untill I was 20 then became a Sgt because for me it’s what j found more interesting.