There are a large number of textbooks for each elementary math course. We may easily agree on what a bad textbook reads like but have different opinions about what makes a good textbook.
In my humble opinion, a good textbook must explain math clearly in a precise and concise manner, demonstrates a variety of problem solving skills, and includes plenty of homework problems of different types and levels. When I teach a math course, I therefore create my own lecture notes with reference to multiple textbooks, including the AoPS series and the series by Larson et al.
My Prealgebra course is leaned toward the AoPS Prealgebra, while the others sit in the middle of the AoPS and Larson series.
Prealgebra students are generally more than prepared for Prealgebra because of the teaching they have received from their parents. They may find a traditional Prealgebra textbook easy and boring. The AoPS Prealgebra goes further/deeper on topics, but just a little (one or two steps) further/deeper such that average students can easily reach. It is therefore a good fit.
Later courses beyond Prealgebra have much more material that has more abstraction, rigor and depth. I think most students of a later course prefer a gentle introduction to the course material to lay a solid foundation and to add a proper elevation. I therefore use the corresponding AoPS textbooks as the supplementary books instead of the starting major textbooks for courses beyond Prealgebra. In fact, some of my homework bonus problems are adopted or modified from challenging problems in AoPS books. Students may read the corresponding AoPS book and try the challenging problems in the book while taking one of my courses or after finishing the course.
K-12 Math Enrichment Courses 