Maybe this is a personal thing, (but judging by the surfeit of books on this topic I'm guessing it's not) but I find stories on Japanese internment camps an interesting counterpoint to the many stories of World War II that find their settings in Europe. It is a similar instinct to watching a train wreck, I think, witnessing after the fact such an obvious breach of the rights and principles we've come to expect as our own. So yes, I get that, and I am a little ashamed for finding it gripping. Heart Mountain was a real place, and the author, who primarily wrote non-fiction before this novel, researched the topic well. This is a good and bad thing, with some parts overladen with the type of facts you don't really see (or need) in a novel.
While I found the topic compelling, some of the characters were barely more than stereotypes, which slowed the story. The tension at the internment site was much more natural and plausible than the accompanying romantic plot line, which I didn't find very credible. I'm not sure how it stacks up against the other books on this topic, but I did think it added an unexplored point of view.
One other note: If you are looking for a summary of the book, you'll find one on Amazon - the Goodreads version is oddly vague.