Loved it, but avoid the breakfast.
We stayed in the Cassa for four nights on our first trip to NYC because we decided to splash out on a really nice hotel. 
The staff are all very lovely and very helpful, especially the doormen. We were very luckily upgraded to another room on arrival as well!
The rooms are stunning, while ours didn't have much of a view it was a very comfortable room. Our bed was super comfortable with a great size bathroom and shower. 
Location wise it's very easy to get to Times Square and you can catch the subway around from there or walk to the places you really want to see. 
The only dissapointing part of it was the breakfast, which cost something like $60 for a very average tasting eggs and sausage on a stale bread roll. Also, the internet was very expensive to use in the room! 
I'd recommend staying here, definitely, but don't eat your meals here as they're really expensive and you can get such good food in New York elsewhere. 
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