Good location, great staff, average hotel.
I stayed at the GEM for a week in December 2012. The hotel itself has a great location and the staff was excellent. Much better service then I've had at more expensive places in NYC.
The rooms were small and for me on business the biggest problem was the noise. Being right on 8th Ave means that early in the morning traffic starts and doesn't stop until late at night. The windows in the hotel haven't been changed since the 80s it seems so they let a lot of sound through. Also, the heater in the room made so much noise that I had to turn it off at night, otherwise every time it started it would wake me. Thankfully for December it was quite warm.
The size of the room didn't bother me like it seems to have bothered others. You can't expect much more in Manhattan.
Would have given the hotel a 4star had it not been for the noise which a window replacement and quieter heater could help.