I stayed here this weekend and it was very enjoyable. Overall, the room is very spacious. It housed 5 (we snuck a 5th person in the room) very comfortably. There are 2 queen beds (1 king is optional) in one bedroom and an oversized couch in the living area. The main bathroom is very large, complete with separate tub and a big walk in shower. Closet space was more than ample for a weekend trip and wouldn't be an issue for a group of 4 for a week stay.
Unfortunately, I didn't spend much time at the pool area, but the little time I spent there, it was really nice. I can definitely see why people stay at Mandalay just for the pool. They had large outdoor food areas and a couple stores to buy whatever accessories you may have forgotten.
The casino part was very nice. Even better was that the tables were kind to me this year. The cocktail waitresses were around quite often, although there was one bad apple in the bunch, but that's ok. Table minimums are what you'd expect for a casino on the strip. don't expect Fremont Street minimums.
I will write more on places inside the complex, but overall, the whole experience at theHotel was fantastic.