Disclaimer: reviewing uncorrected digital proof via NetGalley
I'm not too sure how to review this one. On the one hand, it's very well written, has many strong points, and is generally enjoyable. On the other, it consistently put me to sleep every night and took about 5x longer to read than my usual pace, so . . . I guess it's good fantasy, and most definitively does not follow the contemporary thriller-pacing that we're seeing more of in YA and MG books. Recommended for young readers who enjoy the classics of kid lit, rather than reluctant readers or those who prefer fast-paced stories.
This is a portal fantasy, in which five siblings ranging from early to late elementary age tumble through a window into another world where they discover powers. The third-person narrative lends itself to exploring the world from each character's perspective, allowing for insightful character writing and meaningful personality development, but also feels distant. The journey-of-discovery format means the pace is dreamy and meandering, although there is a clear goal that ties it all together (get home again). There is dark/violent/disturbing content, which may push the edges of younger children's comfort level, but is in line with content from many children's classics. Lots of descriptive writing creates a detailed high fantasy world with some interesting philosophical underpinnings.
In summary, there's lots to like here, but for me personally, it just didn't quite come together. Maybe I was just overtired. Again, I'd recommend this for young readers (and other fans) of dense, fantasy doorstoppers and classic storytelling. Rated 5 for quality, 3 for personal taste.