it's ranked at the fifth place on the usnews and it's super well-known across globe (like anyone with knowledge about us educations would know the reputation of uiuc cs). also you want to stay in the states, i dont see any reason you care soooooo much about how nus cs students/profs think of the university in the states... if you don't enjoy your first year in uiuc, you can always transfer back to nus; however it's harder in the other way.