An average/slightly above average hotel, good location.
Staying two nights over the labor day weekend. The location is very good. If you walk past the hotel away from Union Square, those city blocks are not the nicest part of town with homeless and some sketchy people. I don't feel any dangers in particular but you have to have common sense as walking in any other big cities. The hotel is huge. Check in was quick about 5 mins. The lobby as other reviewers said is gigantic. It makes me feel like I'm in a train terminal. Personally I don't like it but it doesn't matter to me much. I don't spend lots of time in the lobby anyway. I got a room in the tower 3. Room is good and better than average. I wouldn't call it a 4 star even though it's listed as 4 star on travel websites. I've stayed better at Westin and Omni. The room size is about right, not too big not too small. Bathroom is decent size with shower and no tub. Toileteries are Peter Thomas Roth which is a nice touch. The bed is good and comfortable. I slept well. Since the hotel is huge, there'll be a good great mix of people who stay there. In my case, 've encountered lots of drunks, obnoxious frat boys who were being racist toward foreign guest, noisy bachelorette party. The best were a couple who were fighting loudly in front the elevator on our floor and all over the hallway over the guy cheating on the girl numerous times. The girl was yelling and screaming expletives. Some guest did call the security to escort them back to their room. This is the scene out of Jerry Springer at its best.
All in all, it's a decent hotel with clean, quality room, and a good location if you don't pay too much for it.