Pros and cons of a landmark hotel stay
I stayed here for my second time in a decade as a captive hotel-conference attendee, but found the hotel to have the usual pros of an upscale historic property -- and one located at the heart of Chicago's Loop -- and the usual pros and cons of a big convention hotel. 
I was placed, for some reason, on a Hilton Honors floor, so my room was huge, pretty, beautifully maintained, and very comfortable, with armchair, windows that opened (though facing the El train), multiple HDTV channels, big bathroom with nice lotions (though no robes), and, upon request, a coffeemaker. The long and nicely furnished hallways assured that the room was undisturbed by neighbors. There were extra charges for wifi, parking, minibar, etc. Despite the conference crowds, the desk and room service staff were fast, competent, and friendly.
The public rooms are turn-of-the-20th-century elegant, all carpet and gilded ceiling. However, with conference crowds milling about, one's focus was more on avoiding being trampled than on admiring the decor.
While I did not try the well-known hotel restaurant, a quick room service meal was good. On the other hand, drinks and dinner at the informal bar-restaurant off the lobby proved frustratingly slow and mediocre. The hotel's lower level has a Starbucks and informal cafes and stores, which come in handy when the weather is too terrible to venture out. However, it is worth it to make the effort, since Chicago is full of wonderful eateries and shops.