Spent 10 nights here on a business trip. Great service from the staff, although one of the concierge had mistakenly informed me that I couldn't rent a car with the GCC license I have at the time.
Rooms are spacious and well designed. I had breakfast, lunch and dinner at the hotel and I couldn't complain about the food (although I did get bored of it near the end). I love the bar/restaurant they have, watched a few rugby games and had a good time and met new people there.
The hotel is actually pretty far from the city, about 20 USD cab ride to the City each way. So if you are looking at frequent trips to the city it is wise to avoid the hotel. Although city buses are available. Within the Yas Island itself, you can do many things, I visited all the attractions in the island, Ferrari World, Water Park, Yas Marina Circuit (Drove the Aston Martin at the track!), etc.
I would go back again, maybe even go back for the F1!