The LondonNYC is a good qpr 4-star hotel. It was originally the Rihga Royal, and briefly a JW Marriott.
The rooms are [all] suites, and are a good value on a per square foot basis. If you are traveling en famille, you might give it serious consideration.
The LondonNYC's building was originally planned to be residences. Part way through the construction, plans changed and it was completed as a hotel. As such, beyond the restaurant in the lobby, the hotel has no other hotel amenities.
Despite the sentimental ties from having my wedding reception in one of the penthouse suites at the Rihga, I can second DavidO's view that the rccps is also my favorite hotel in NYC.
Also shoe-horned in a building not built to be a modern hotel, the service experience at this property is unmatched in NYC. If you can get a room on the 9th or 10th floor, you'll be just above the tree line.
For £100 difference, the choice is easy.
Also make sure to book the rccps via Amex FHR, virtuoso or ritz stars for some added benefits. Pm me if you need details.