I have purchased Newport H20 Keens every year as a go to shoe for my kids. Keens are amazing because : they're easy for the kids to put on, they protect my kids toes, they fit well and comfortably for the kids, and they throw into the washing machine fabulously (I don't dry them).
My daughter has recently grown coordinated enough to wear flip-flops and loves to wear them everywear, so I thought this would be a great compromise- a little more stability, protect her toes, same keen quality.
It's a great shoe, but I think I'll stick to the newports. Our newsports typically run 1/2 to a size larger I've noticed, my daughter has been able to size up without any problems. The waimea's fit maybe even a bit smaller. She's currently wearing size 8 in her vans, and although we purchased a size 9- they fit the length of her foot perfectly. The back strap was a bit too long to offer much stability, it typically slid down when she walked around the house. One more thing I noticed, is that the sandal was stiff so it made it difficult for her to walk, especially since the backstrap didn't hold them on. She would drag her shoes around, but then again she tends to do that slightly with flip-flops anyway.
All in all, it's a nice shoe, maybe if she was a bit more coordinated it would work, it was definitely aesthetically pleasing anyhow but we still returned it and stuck with her newports.