I have stayed at the JW Las Vegas (Summerlin) many times, and I love the large standard rooms, although I've been fortunate enough to get upgraded to suites often. The suites there are typically 1000 sq ft. The service has always been impeccable.
Some of the best service I've ever received anywhere was at the JW New Delhi Aerocity, from the nice welcome, and having already been checked-in before I arrived, I had two escorts to my room, showing me all the room features, bringing my luggage up at the same time, and acknowledging my status. Service at all the restaurants were incredible as well. On more than one occasion the chef came out to ask how I enjoyed the meal & if there was anything else they could prepare for me! Highly recommend