This is one of the better MG mixed kid books I've read (in that the plot doesn't entirely revolve around the mixed kid protag coming to terms with her racial identity). The story escalates very quickly and by far the best parts for me were when Casey and Paw Paw (Tai Paw in this story) were back in Chinatown with Mr Jeh and Gilbert. Learning bits that connect this story to The Child of the Owl were great.
There's also this fantastic bit where Stacy is thinking about bigots (that's the actual word Yep uses in the novel) and realizes that someone can seem like a nice person and still be bigoted. I thought that was a great message to put in a children's novel. I was less thrilled with the racism (and prejudice against mixed kids) was compared to other prejudices. I think it's great to tell kids that they should be accepted for who they are and accept others for who they are, but experiencing racism is different than having people tease you because you're kind of goofy sometimes (I can't remember the exact comparisons that are made in the book).
Because the story happens so quickly (over the course of two days), it felt a little rushed to me and the ending feels a little too neat. But other than that, this is a pretty good contemporary MG novel.
ETA: The book is pretty heavy-handed at the beginning, but it improves as the story goes along.