Just finishing up a stay here. Overall it's a nice hotel. Gets extremely busy when they have large conferences as they do have a lot of rooms. Connected by walkways to the convention center, Wintrust Arena and Hyatt (via the convention center). The place just feels like it's missing something though. Room designs are more modern contemporary but also more on the spartan side like a Courtyard - no closet door, no tubs, smallish work area although you can work from the sofa with a small moveable table. One of my colleagues did not have a phone in his room. Rooms are decent sized though. Sofa does make it a bit hard to open and close the curtains. Equipped with a coffee maker, nice TV and outlets with USB chargers in the right places though.
The M Lounge (for Plat & up) is spacious and very nice but in typical cheapo Marriott fashion, $10 for a darn beer (i'm a Starwood guy and used to the free drinks at many SPG properties). Happy hour snacks are alright but lounge is closed on Friday/Saturday except open for breakfast every day until 9am. Breakfast is ok but it's pretty much the same thing every day.
Staff was fine although the last day here, they did not bother to clean the room. I also got an upgrade notice on my Marriott app a couple hours after I checked in but when I called, they said I already had a nice room with a lake view...