KU is a wonderful midwestern flagship. My S also had Mizzou, OU and Iowa (only one we didn't visit) on his list and in the end chose KU, although he knows he could have been happy at any of them. He just really felt at home on the KU campus.
As you noted, the campus is gorgeous, and since (unlike the rest of KS) it is high on a hill, the views are stunning. School spirit abounds and everyday you will see tons of kids sporting KU apparel. There is pride in being a Jayhawk. The town of Lawrence has a great relationship with KU and Massachusetts St. has tons of restaurants, coffee shops. galleries and stores. There is a shuttle at the KC airport that stops in Lawrence, so travel for my OOS student has not been a problem. He has found the students, faculty and support staff very friendly and welcoming and has developed great relationships with a few profs. The sports scene is amazing and the 4 year fixed tuition rate is great for budgeting the cost of your education.
My soph S has enjoyed most of his classes. He has had a few large lecture intro classes (chem & mythology) but for the most part class sizes have been 15-25. He likes his advisor and feels he has been helpful. When S wanted to change his major he received the guidance he needed to make a good decision and was able to complete the process easily. I'm sorry I don't know any specifics about the poli sci program.
My S has just loved KU. Good luck, you have some great schools on your list.
Why KU - The University of Kansas University of Kansas YouTube - KU's Channel