Unless there is a great reason (really heavy bags, one of you is not as mobile), get on the L and take the Blue Line, most likely to State and Lake, where you'll probably get on the Red Line. Google Maps is very accurate for CTA transfers and such. An Uber will cost you a ton and possibly take longer (or as long) depending on traffic. At minimum take the L to the Loop and grab a taxi/uber from there, but depending on which hotel, chances are the Red Line will get you close enough. The price is $5.00, and you can tap and pay or download the Ventra app and buy a multiday pass, no need to stop at the machines. You do NOT have to tap out. The fare back to ORD is only $2.50, so $7.50 each for RT airport transport.

One note: Ubers have a designated pick up spot at ORD, and it's sometimes more of a pain to get there with bags than just get to the train. Should you want a paid ride, use the Curb app, which works like Uber/Lyft but is the taxi app. It's often lower or comparable.

Have a great time!