Indiana University-South Bend is a regional IU campus serving north-central Indiana with a four-year degree experience at a lower cost than IU Bloomington. You're getting an IU degree, IU coursework, and IU standards without the flagship prestige or flagship price. The campus is smaller (around 5,000 students), which means more accessible faculty and less anonymous lectures, but it also means fewer campus resources and a less vibrant student culture.
South Bend itself is a working-class industrial city with genuine character but not the college-town vitality of Bloomington. Your classmates are more likely to be local, commuting, or working while studying. If you want an IU degree but need affordability and smaller classes, this works. But be clear-eyed: the regional campus brand carries less weight than the flagship, and the campus experience is less polished.