Spend a bit more and stay elsewhere.
My wife and I booked this hotel for a short stay visiting our daughter who lives in manhattan and chose it as it is a short walk from her apartment. 
First of all the photos are deceptive and it is amazing what a good wide-angle lens can do. Our room was a 'standard room' - #417 on the fourth floor. There was nothing 'standard' about it. I am well travelled but this was the smallest room in any hotel I have stayed in anywhere. Boutique should not translate into tiny. I guess the bed size can be referred to as a small double. I am 5'8" (1.72m) and the bed barely accommodated me. Also two adults (and we are not large by any means) are extremely cozy in a bed thats 4'0" (1.22m) wide. 
We were traveling with carry-on bags, and I can't imagine how two persons with normal suitcases would be able to open them. The window was located about 6'6" (2m) away from the bed down a slot that was as wide as my shoulders and looked into a light well. My immediate thought was - "great, no street noise". Well, that was until we turned on the air-conditioner - what a racket. Switched off the airco. and opened the window after pulling up the blind. half of the window was blocked by a vertical air duct, and it would not stay open. Jammed a shoe in the opening to keep the double hung window ajar so that we could get some air. That lasted all of five minutes as the noise from the other air-conditioners serving other rooms opening into the light-well were also noisy.
The clearance between the door opening into the bathroom and the toilet was less than 1mm. As an Architect, I marveled at the preciseness of the construction.
To be fair, the lobby was nice and the desk clerk, as well as the bellmen were polite. On checkout we asked the desk clerk if all the rooms were that small. He politely answered that we did book a 'standard' room, and the next time we stayed we would be upgraded to a 'deluxe' room. I guess $300 per night at this place gets one what I would call a sub-standard room. I know Manhattan is expensive, but this is a lot to spend for mediocre.
Spend $50 more and stay elsewhere. The place was clean though, and there was plenty of hot water, and despite the small size, the bed was comfortable (for 1). It wasn't worth complaining as we were only there for 1 night. check out my other reviews - they are generally positive.