I've been to The Manhattan Club many times. The rooms are usually quite nice. Some are bigger than others. My anecdotal evidence is since you don't own there they might give you a better room and hope to talk you into buying. Before you go they will hunt you down and get you to sign up for a sales pitch. I did this once and that time that I did I had an absolutely enormous room.
Of course that could have been coincidence as well.
I'm not saying that you should sign up for a sales pitch (I'd actually recommend the opposite), but maybe giving them a reason to impress you will entice them you give you a better room.
The location is great. You are very close to Columbus Circle. We usually go there and hit the Whole Foods there to get snacks and bottled water to keep in the mini refrigerator.
Carnegie Deli is like a block away. We usually get take out (we can split one sandwich) and bring it back to the room. Oh and a slice of cheesecake. Very nice, and the room is nicer than the restaurant.
There is a bakery around the corner (okay there are tons of bakeries around the corner) but one that is particularly good for bread and croissants. I'm going next week so I'll look up the name if you are interested.
I don't believe there are laundry facilities. I only go for short stays so have never needed laundry. You could check their website.
Be sure to go up to the lounge at the top. Don't eat breakfast there. They charge. Sometimes they have cookies in the afternoon (free).