Great fun for a couple of days
We just got back from the Arizona Grand Resort and we had a very fun time. The property is beautiful and the rooms are comfortable. It's good for a nice, short trip. While 7 acres sounds like a lot, it isn't all that big so after a couple of days you're pretty much done -- and by that time you have gone around on the lazy river a good hundred times or so. 
I also must admit that my family is a bit spoiled/jaded as we've been to Atlantis twice which is like the king of water parks. It's like going to Disneyworld and then the county fair. Both are fun, but the fair seems a little more rink/dink and loses it's charm quicker. But let me stress -- still fun. 
The resort will try and up-sell you a room closer to the water park for $20 more a night. I don't think you need it. Our room was plenty close enough and I found that we did not go in and out of the water park. You're pretty much there for the long haul. 
During the summer they show movies on Friday and Saturday nights -- "Dive In Movies." You can either watch from the wave pool or in a chair on dry land. On a warm, balmy night, you just can't beat this. 
There are also several "normal" pools around the property which are nice when you don't want to be in the Oasis. We called Pizza Hut to deliver and had dinner by the pool while the kids swam. 
There are two restaurants near the property which are affiliated with the resort: Aunt Chilads and Rustler's Roost. You can get a golf-cart style limo shuttle to and from -- which is amusingly fun for the kids. 
We took a short side trip on our last day to do some real tubbing down the Salt River (see separate review). It's fun for the tween and up set. 
All in all, it is a good time for a short period of time.