For what it's worth, the Heathrow Marriott is a really nice property. Big, comfortable rooms a 'la USA.
My only complaint, and the hotel is not at fault because it's local rules, is that free transportation is not provided for the 1 mile journey to the airport. One has to pay $8 for the Hoppa Bus.
The LHR Marriott can be booked for 99 GBP, not US dollars, which converts to about $150 USD today.
I suspect the $99 for the Amsterdam Courtyard is really 99 Euro which would be about $132 USD.
The Whippany Courtyard is $84 USD on a Saturday night.
Are you using comparable days of the week in your posting?