We stayed at this property from Jun 19-22 and enjoyed it immensely. The hotel lives up to the Four Seasons' reputation and is a nice change of pace from the casinos and smoke which are easily accessible through the convenient door to the Mandalay Bay hotel.
Dining at the Verandah is a delicious alternative, but there are tons of other restaurants to check out around town and I would recommend getting out a bit and sampling other fare. We liked the dinner buffet at the Wynn Las Vegas.
The pool was nice and poolside dining is from the Verandah. A standard touch is a pitcher of ice cold water and cups when they set up your chaise. The Mandalay Bay pools were fun but didn't seem particularly clean- you could see the sand and feel the grime in the lazy river. And the wave pool activates once every 30 seconds as opposed to going for 6 minutes, stopping for six minutes and going again and the bottom is rough enough to scrape up body surfers so you might wear a shirt for that activity.
If you like good service, I'm not sure you can beat the FS. The doormen and bell captains were EXCELLENT. The lobby greeter was helpful (I asked if you could charge dining items at Mandalay Bay to the FS-- you can, but you should bring a credit card if you intend to rent or buy an inner tube) and the front desk staff was FANTASTIC. The concierge staff was super helpful and helped us book tickets to Mystere at Treasure Island. They also helped my husband charge his cell phone because he had forgotten his. That's service. House keeping was also prompt and everything materially was as you would expect of a FS property.
Spa was also very nice. Small-ish workout area but everything you would probably look for. Massage by Nicole was fantastic. (Visited the hair salon in Mandalay Bay and liked that very much as well.)
Definitely recommend this property. Couples may also want to consider the Wynn.

Let me start off by first saying that I am a frequent guest of Bellagio and Wynn but they where sold out which led me to the Four Seasons. I must say that this is the only hotel I will stay at from now on while I am in Las Vegas. The service was fabulous! Every single person, even the cleaning staff sweeping the floors, will give you a big smile and greet you. It's nice, because you don't have the sense of being surrounded by unhappy staff. You feel welcomed immediately and completely at home. Everything from room service to housekeeping, but the best service is from the Concierge. This hotel has SERVICE, SERVICE, SERVICE, the best I have ever had. The Concierge (Scott) is VERY well connected and is able to secure seats for sold out venues and able to get you past line/cover charges at all the different night clubs if they want to. The Concierge is amazing and the best I have ever dealt with! Wynn and Bellagio may have better restaurants but I am convinced that Four Seasons is the way to go. My stay at the Four Seasons was nothing short of exceptional. I have stayed at several other prime properties in Las Vegas before, but this was my first stay at the FS.

This was my wife's and I first vacation away from our kids. We spent 5 nights at the Four Seasons Las Vegas hotel at Mandalay Bay. Though we only stayed in a "Supeior" room with a king bed and a view of the pool/airport, this hotel was everything that it was supposed to be. It made for a memorable vacation that was difficult to come home from. Let's start with the amenities and service:

* Pool service with escorting to lounge chairs (never a wait), constant service, free ice water, popcorn, ice pops, oranges, pineapple, glasses cleaning, etc. The pool service was an oasis from the craziness of the Mandalay Bay complex.
* Free access to the spa/workout facilities. At most hotels you pay daily for this, here its complementary to guests. Want to leave your stuff in a locker while you stroll over to the wave pool at MB, use the locker. Want to workout on a treadmill before going to the pool, take a shower in the locker room before heading out. Amazing (spa services though exspenive were great).
* Room was ultra-comfortable. Stinks having to come back home and sleep in ordinary bed. Never a problem with cleaning of room, would always be done multiple times a day.
* Easy, quick access to rental car through valet. (There is a minor charge however)
* Quiet, elegant dining at Verandah cafe (espeically Weekend morning brunch)
* Though our kids were not with us, it appears that they are a very kid friendly hotel.
* Every single time we bumped into a hotel employee, we were always greeted with a hello.
* Though it is at the far south end of the strip, it does have quick, easy access to I-15 which is easier and quicker to drive up than the Strip itself (and quick to the airport).
* Access to MB pools, but ability to get back to quietness of FS
* No crowds at all. When walking through MB and especially Bellagio, I was amazed at how crowded these places where, especially the check-in area and valet/taxi area. Never ever experienced this at FS.

What I basically found since FS is a HOTEL and not a CASINO, they care more about the service than the casino dollars. With good service they make you want to come back (and that is exactly the way my wife and I feel). Unfortunately, we had too good a time on vacation and its difficult to get back to normal life after being pampered at the FS

I chose Four Seasons because I was traveling with three small children (4,3, and 1). We went to Vegas during one of the busiest weekends (Memorial Day), and our selection of this hotel was a wise one. They welcomed my kids so nicely. After 5+ hours on a plane, it was so rewarding to have them received so well. Yes, I know Vegas isn't for kids, but I think so long as you don't expose them to things that are really inappropriate, it's fine. The room was very nice, the pool was nice and they are constantly coming around offering various things (sliced oranges, clean your sunglasses, spritz you with evian, etc...) - very nice and pampering. I would hang up the phone with housekeeping with a special request, and literally, they were knocking on my door in minutes. I had a party for my husband's 40th at the La Sala Room in the Veranda, and it was outstanding. I would say that this hotel EXCEEDED my expectations in all aspects. The only thing I didn't like about it, is that if you are tempted to visit Mandalay Bay Pool, Casino, etc...it is like a being at Seaside Park Boardwalk in NJ on the 4th of July.