Investing in Illinois pitfalls?

[Michael King]

I have a colleague at work who owns 4 rental properties, I know at least 2 of them are located in Illinois. Illinois being the glamorous, tax happy state that it is...I have some questions. Well one mainly. What is the deal with selling a property in Illinois and being taxed on the sale if you don't reinvest in Illinois? Kind of like they have their own 1031 type of exchange going on. 

I'm a buy and hold guy, but if I bought and thought this is a bad deal...what does the exit fee look like?  

I don't have any financial information on the deal yet, just looking to the future and gaining knowledge for now. I appreciate any feedback, thank you.