Pros
I've had an amazing experience at IU Bloomington during my graduate studies. Bloomington is a wonderful small town that offers everything a graduate student could ask for: clean, efficient, and free public transportation for students, vibrant cultural events, and diverse cuisine. The town is very walkable and bike-friendly, and the surrounding rural areas are clean and almost pollution-free. From a research perspective, there is excellent support for students and access to great facilities. Access to the Big Red supercomputer has been particularly valuable. Funding is also sufficient to attend two or three conferences per year. PhD stipends are reasonable, and because rent is relatively inexpensive, students are often able to save money.
Cons
A major downside is the current university administration. Many people on campus are unhappy with it, as it is widely viewed as having political priorities. The administration has also made several management mistakes and has faced criticism for actions that some see as attempts to limit free speech on multiple occasions.