I'm a fan of this hotel - it's only the top 5 floors of the Mandalay Bay hotel but they're beautiful and it's quiet with gorgeous rooms.
It has it's own private entrance away from the Mandalay Bay but it connects to all the major sections of the main hotel and is an easy walk or elevator ride to the casino.
This hotel also has it's own private spa, pool and two restaurants. I also especially liked that in order to access the rooms from the main Madalay Bay casino you have to use your key card to get into a small room with the elevators. Nice, it keeps random folks from trying to "sight-see" the Four Seasons rooms or hallways.
It's not crowded at all - we rarely saw more than 1-2 people in the hallways or downstairs entrance area and we never had to wait more than about 5 minutes for a cab out front.
It's also only about 5 minutes from the Las Vegas sign so we were able to stop by twice and take some photos without much of a crowd.
The hours for the hotel pool/spa are not very late as we found on our first day when the pool closed at around 5pm or something - so I wasn't able to soak in the hot tub as I'd hoped after a long day of missed flights and stress... wasn't happy about that but it is what it is I suppose since it's not a huge large resort on its own.
Our room was BEAUTIFUL with a direct view of the Las Vegas Strip - we could easily see all the way down to Paris and beyond and had a beautiful view of the Luxor which is right next door.
We stayed with some other friends and family who didn't have quite as spacious of a room as ours but their room was still beautiful and tastefully done with lots of amenities like a recessed bar area, two closets and a large spacious bathroom area with lots of counter space.
We ate at one of the two Four Seasons restaurants - Verdana - many times and loved it. Delicious food. I'm sure their room service is also phenomenal if it's as good as it typically is at Four Seasons hotels but we were hardly in our rooms long enough to order any!
We will be staying here any time we come back to Vegas - service was great, beautiful rooms, no crowds, price was decent for Four Seasons (probably bc they want you to spend the money in the casino and not on the rooms), and we like being further down the strip away from all the hubbub.