Nice Hotel, great price and a great location
If you want a clean, affordable, modern hotel located in a nice neighborhood with plenty of restaurants and just a few subway stops from all of the attractions, this is the place for you. If you want to throw a party in your room for more than 2 people, don't stay here.
The Gem Hotel is 1 block for the ACE 23rd street subway station (8th avenue lines). It located nice neighborhood with plenty of restaurants (next to the hotel that was both small grocery, bar and restaurant). A few blocks down 8th ave was a number of restaurants like the Rocking horse Cafe - great, unusual Mexican food and Margaritas). The High Line is a short walk on 20th and 10th ave, We were 1 stop from Penn Station and 5 stops from the WTC memorial.
The staff was very nice. Our room was clean. The bed was very comfortable. The bathroom was modern. The AC worked great (it was over 100 during the day). There was free WIFI. There was a nice rooftop patio with umbrella-ed tables. It had a nice view. On Sunday morning we grabbed coffee and fruit from next door and a newspaper and sat up there for an hour. 
Check in was at 3pm and checkout was at 11am (pretty standard). However, we arrived at 11am and left our bags, had a late check-out (1pm) and again left our bags. 
What more do you need? You are in NYC and presumably, there to go out on the town.