Nice location to see / do stuff along the Mile. If you want to visit things farther out, just take a cab. The staff was very nice / accommodating. I took a cooking class and came back with leftovers. When I asked one of the front desk staff members if I could stash it in my mini-bar fridge, she said that wasn't a good idea since it wouldn't keep it cold enough. She then offered to have a fridge delivered to my room or to hold it till I checked out. Every staff member I interacted with was so nice [Bar 151, housekeeping, front desk, bellmen]. I thought the room was super-clean, and it had everything I needed for the short stay. I'd go back again on my next trip to Chicago.

This hotel is noisy and bustling. We got off on a bad start when the rooms we had booked WEEKS earlier were not available. We booked rooms with two beds and none were left. The desk clerk did his best, though, and got us suites with roll-aways. The rooms were lovely. EVERYTHING costs a lot here, but most charges can be avoided. Don't drive here, parking is very expensive. Join the Gold Passport Club - even if this is your only Hyatt stay ever and you are partway through it! This will get you free Internet access and a late check out. Both needed for a convention.
The concourse to the west has reasonably priced lunch restaurants. I.e. Potbelly's and Cosi, etc. Dont eat the Hyatt's overpriced convention offerings.
The location is wonderful - convenient to the Miracle Mile, Millennium Park, the Loop, Art Institute, Navy Pier, Picasso, and not far from the Museums.
The staff seems joyous! Everyone we interacted with was friendly and seemed genuinely happy. I was shocked by this, because the loud, busy atmosphere and the constant stream of novice travelers would drive me crazy if I had to deal with them.
Don't come for romance, quaint surroundings, upscale treatment, or relaxation. However, if you have a convention here or a great deal from an onine travel site, don't hesitate.

Wonderful staff with great service, very accommodating. Really enjoyed our stay here. The location is excellent, fitness center is large with a lot of equipment options. There is a bar on the second floor with a great view of the Wrigley building. We had a great experience during our stay at this Hyatt.

This is a huge hotel, and many of the rooms have been recently redone. Rather impersonal place, but functional and in a reasonable location once you figure out transportation. Most of the restaurants and interesting pubs are across the river, off Michigan Ave, and if the weather is mean, it can be quite a hike. The underground meeting rooms are a huge labyrinth of rooms, poorly marked, and frustrating to navigate. This hotel spans two blocks, and has underground connectors beneath the street. Unless you are careful, you can come up on the wrong side of the block. Even if you ARE careful, you may find you have to go back and forth using the tunnel or the 2nd floor bridge between the buildings. Gets old FAST. The restaurants are just OK and uninspired, and when there's a conference there, the line at the Starbucks is maddening. After many stays, you can figure out how to travel underground/indoors for up to 4 blocks from the hotel, but other than weekday business hours, those hallways become almost scary, because there's nobody in sight.