Coming from downtown, take the L.
Coming from O'Hare, students take the express Pulse bus
https://www.pacebus.com/route/pulse-dempster-line from the building where the rental cars are (there is another, similar-looking bus that stops at every stop, so look carefully before you get on). It goes straight down Dempster and makes lights turn green. Takes about an hour to Evanston. Like two bucks.
Driving O'Hare to Evanston the other day took me 40 min. I always get a rental car and stay in Evanston or Skokie; essentially, I'm both lazy and not wanting to spend my short time there on public transportation. Taking public transportation does make sense if you have the time and energy.
Parking is a little annoying in Chicago, particularly paying so much for street parking (>$14 for 3 hrs), tho I found spots in River North fairly easily three times last weekend. Might as well park in a garage, basically. If you decide to stay downtown somewhere, budget for parking. If you have a rental car and drive to Evanston for the admission tour, they will have you park in the Segal visitor parking garage.
I haven't ubered there lately, but there's no reason why you couldn't. Certainly a viable option.
I think you need to decide where you want to stay and what else you want to do in Chicago while you're there. Are you also visiting UChicago?