If you have watched the anime adaptation and are yearning for more of Holo's simple yet intricate and extremely charming character then i recommend reading this novel.
Although there are slight discrepancies throughout the novel and anime, not too much stands out. The novel exhibits the themes of the loneliness in a much more apparent and clear representation through the emotions that are being disclosed to the readers.
Overall a very good read for either those who are new to the series or have read or watched either manga or anime adaptations and are looking for a wonderfully written work of art which in my opinion is masterfully crafted.