Great location, customer service and cleanliness need improvement
Booked this hotel through Hotels.com and got a pretty good rate comparatively speaking. Unfortunately our experience got off to a rocky start upon check-in . Although the front desk clerk was pleasant, he could not find our reservation. He brought someone else over to help and neither could find our reservation. We showed them our confirmation e-mail from Hotels.com, but that didn't help. They offered to book us in a room until we sorted things out, but that would have resulted in us paying again. We already paid in full on Hotels.com, so I knew that would only further complicate matters. We eventually left the front desk area and called Hotels.com ourselves from our cell phone. We finally got through to someone who confirmed our reservation for that day and at that hotel. The Hotels.com agent was able to provide us with the Hyatt reservation number. We went back to the desk and they were able to pull up the reservation. They had to call a manager over because apparently the reservation was entered for a month prior (March). I kept the Hotels.com person on the line and she offered to put me on hold and contact the hotel directly. She did that. The Hyatt front desk manager finally came to the desk and was able to enter a new booking. She explained that the hotel receives a report from Hotels.com and sometimes when the data is manually entered into their system a mistake can be made. Originally upon checking in we asked for a Chrysler Building view. When we finally did get a room (after about an hour process) we certainly weren't facing the Chrysler building and walked into a stale smoke smelling room. We already wasted an hour at the front desk with check in and we certainly weren't interested in getting our room switched. We were already late for an event. 
I just can't believe that the hotel wouldn't have called Hotels.com directly after we showed them our confirmation. Instead they told us that the person that might be able to help was at lunch. So, that is why we called Hotels.com directly to resolve the situation. The "Grand" Hyatt should be able to figure something like this out. Then even after it was found to be the hotel's fault they couldn’t even honor our request for a specific room location? 
Aside from that the location of the hotel is great. It literally connects to Grand Central Station. The room decor was modern and tasteful. Unfortunately the shower seemed VERY dirty. The walls were tile, but the white floor of the shower was stained many times over. The shower door opens-in, which would make it difficult for the cleaning crew to clean behind the door. This was overly apparent! We did not feel comfortable without wearing flip-flops. The bathroom was small, and our "Grand King" room did not have a tub (although given the cleanliness issues, we probably wouldn't have used it). Aside from that, the room was pretty good. The size was fine and aside from a loud elevator bell across from our room, we had no other problems.