Our deluxe balcony room was wonderful. Huge and with a good view of the Sphere and other fun lights (also a big boring parking lot haha). The lack of 5 star rating is for 3 things:
1-It is not very walkable, unless you are willing to go through a smoky casino for 15 minutes. No good way to get outside.
2- The pool and hot tub, which we really wanted after our days of bicycling and hiking at stunning Red Rock Canyon CLOSED AT 4PM. Seriously ridiculous.
3-High Resort Fee but as I mentioned, no pool or hot tub amenities. The staff didn't even try to reduce these fees, wouldn't ask the manager.
Valet was EXCELLENT. Lobby was pleasant, and our room was great. We chose Signature Suites MGM because we had tickets for Ka Cirque de Soleil show, which was spectacular. Again had to walk through the smoky casino and bars on the way, as there is no exterior access to theatre. (I along with many other people, am allergic to cigarette smoke, as it triggers migraines.)