There is an option on booking (which I ticked) that says 'upper floors if available'. However, I was put on the lowest floor possible with view of the backalley (or better a view of the walls of the building opposite). Together with relatively low ceilings and the many floors above this did feel claustrophobic and oppressive although the room itself was decently sized. I stayed in low season and there appeared to be still a host of rooms available so alongside with the fact that no-one said anything at check in (I would have expected at least a "sorry unfortunately we are all but full so we can not give you the room requested") it felt as if the option was simply ignored, possibly because what I had booked with a discount through booking.com. no coffee/teamaking facilities in room.
I guess had I sayed on a higher floors the overall score would be higher, but the claustrophobic feeling results in relatively low ratings for both comfort and value for money. Room was fine for a night (and just to sleep in) though, and if you don't bother about feeling like being in the belly of a whale you will be perfectly OK also to stay longer.
comfortable bed, clean, decent size room, large bathroom, friendly and helpful staff. quiet (except when the bar/restaurant besides trashes the bottles in the backalley at the end of the night, but that doesnt last long so isn't an issue).
central location (if you like staying around union square), feels perfectly safe.