I loved my time at IWU, and I don't regret my choice of undergraduate college at all.
I would recommend IWU to students who are looking for a strong liberal arts education, who want to be on a campus large enough to have options but small enough to feel like a community, and who are seeking a place where they can interact with and get to know the faculty. I chose IWU because the college has a strong program in my major, and I wanted the opportunity to learn directly from professors, not TAs. I also loved the 4-4-1 academic schedule with Mayterm opportunities for specialized or travel-based courses.
As with any college, it's not ideal for everyone. IWU doesn't offer a lot of specialized or technical majors, so it may not be the right choice if you want a very focused or unusual degree. Also, it probably won't appeal to students looking for an urban environment. Bloomington-Normal is a good-sized town for the midwest, but it's not an urban by any means.
Things you might not have thought about but should: An undergraduate-only institution gives undergrads the opportunity to work as teaching and research assistants. IWU has several strong study-abroad programs. A smaller college provides more opportunities for leadership roles in various organizations.