As an engineer and an alumna, I recommend SIU-Carbondale! I majored in Mechanical Engineering and graduated from there in 1998.
I've learned in my career as an engineer that it matters WAY more how WELL you did in school than it does WHICH school you went to. In fact, my first job after graduation based my starting salary on my GPA and class rank. Bigger class makes the ranking a lot harder to get. The engineering class I graduated with was maybe 200 people? And of those, maybe 40-50 were MEs. I was one of only 3 women, but I digress...
SIU's engineering department is small enough to get the help you need, and large enough to provide the education you need. I was accepted to U of I in Urbana-Champaign, but didn't go because I didn't like the feel of it there when I visited.....plus, SIU threw way more grants my way!
Plus, the year I graduated, our class at SIU out-performed the U of I class on the EIT exam (I think it's called FE now? Fundamentals of engineering....first step to getting your Professional Engineering licensing....8 hour exam from hades

). SIU's graduation rate is much higher too vs. UofI.

They just have a much better reputation for their program. I'm holding my own with alumni from UofI, UMRolla, Purdue, Michigan, you name it. Your degree is 95% what you put into it....I'm a BIG believer in that!
Whichever you pick, best of luck. Engineering isn't an easy major, but it can be quite worth it later!
Diana (go Salukis!), proudly working as an engineer in Phantom Works at Boeing!