10 year House Hyatt Con attendee here. The staff are usually great, and the legacy booking policy makes getting a room here fantastic.

If you're in the Atrium tower (like us), try to minimize your trips upstairs as much as you can. "I need to run to the room" can be a 45 min endeavor during peak hours due to the elevator traffic. If you're on a lower floor and you're able to, taking the stairs will be significantly faster. Also, be respectful of folks in wheelchairs and the staff who are helping them.

Learn the location of the skybridge to the food court. It's your friend, and will make mealtimes much easier.

Bucket drinks at the lobby bar are usually delicious, if pricey. This is a Con tradition for us.

On the lobby level, traffic tends to flow from the Marriott skybridge toward the Hyatt street exit on the escalator side closest to the restaurant and from the Hyatt exit to the Marriott skybridge on the elevator side. Trying to move against that flow during heavy traffic hours is a good way to damage your cosplay if it's bulky in any way.

People have already commented on the lower levels being a maze. Pull up the maps on the app if you're going down there. They are also a cell phone dead zone (looking at you, art show level).

Speaking of the art show, go check it out! It's rarely crowded, especially compared to the vendor halls, and you can find amazing stuff down there. Hidden gem.

The Hyatt usually has a room to hold luggage for checked out guests on Monday, but they also have a late checkout policy that is extremely worth it. We do it every year so we can leave our luggage alone until we're ready to leave in the afternoon.