I've had the pleasure of bouncing around many a Phoenix resort. Montelucia is by far my favorite. It's pricey, so don't start thinking it's an affordable place. It's not. But it's worth every penny. During summer months, you can certainly land room deals, so that's your best way to go.
For the life of me I never remember the names of the pools. The back pool is more of an adult-only pool. No kiddies. So that's nice. But the front pool, up by Prado, is where the action's at in my opinion. It's nice to take a dip and then swing by the outdoor bar for a couple cocktails.
One of my favorite things on earth is Joya spa. That's a separate review. One thing on that though: Plan to stay the entire day. So much to do and see, even if you only have an appointment for one service. Go sit in the indoor pool or hot tub for a while first!
Whether you go for one night or a whole weekend, you'll definitely feel like a new person afterwards.