Brave Story is like the Thomas Covenant books, but you know, for kids! It is a slow but ultimately likeable adventure about a Japanese school boy pulled into a fantastical world of strange creatures and magic. The basic idea is common enough in manga that has its own sub-genre, (Iseki?) but sure, one more never hurts.
The story is told simply but well. The protagonist is a good kid who plays a lot of video games and just generally wants to do what is right in any given situation. And the fantasy world he is pulled into is in part a reflection of his own mind and experiences, so there are challenges and dangers but nothing beyond what you would see in Final Fantasy III or the like. I thought it was enjoyably non-edgy, just a sort of warm and interesting novelization of a JRPG adventure. Really the scariest part of the book was the first 250 pages set in the real world, where the kid's parents are going through a fairly brutal divorce. And despite the over all simplicity of the plot and structure and characters, I did reliably enjoy the actual descriptions of the scenes. It's not a terrible book for a long relaxing easy read.