I took my 4 and 8 year old boys over Christmas break so it was pretty busy but they absolutely loved it. I was surprised they played so long as I thought they would get bored with the handful of things the attraction offers. But we ended up being there for 5 hours. The rides were ok but what the kids really liked was the jungle gym which is where they spent most of their time. It was relatively clean and organized and the staff was attentive. I liked how much seating was available for parents and they even had a parent lounge that was quiet and cozy.
So why the 3 stars? It was expensive and not a good value for how much you spent. We went on comps passes the kids got from a diamondbacks game so it made it worth it for us but I won't be back to pay full price.
TIPS: They allow outside food in so bring your own. The cafe is as expected for an attraction like this-gross and over priced. They do minifig trading just like Legoland in California so bring your figs to trade. The kids need socks to play on the playground. You can buy them at the cafe for $1.