We stayed at The Signature Towers at MGM - separate towers (connected by moving walkways) at back of MGM. Very luxurious - sheets costs a fortune and feel wonderful. They are condimium places, currently selling for several million I think.
All very new - tower 1 not even finished yet, you get great concierge service, large TV, proper lounge in the room, kitchen area with brand new applicances so you can cook if you want. Great shower, two sinks in bathroom and jacuzzi bath. Get a room over looking strip (just off strip but great views) Hardly used any of it..busy on the strip.
have a great time :-)
I saw those in November, they looked damn nice.