Within the Samick/Young Chang and Yamaha/Kawai columns, the various brand names or model groupings are organized approximately as the respective companies themselves position them in the marketplace by price and features. The brands within the Chinese column are organized by approximate overall recommendability, which also tends to fall along lines of price and features, though not uniformly so.
Using price as a factor in rating pianos reflects the fact that, in a competitive market, price is a reasonably good indicator of quality. But for this to be true, "quality" must be properly understood to include all factors that consumers value — not only an instrument's performance, but also the brand's reputation and its track records for durability, reliability, warranty service, and resale value. This is especially relevant for consumer-grade pianos, where purchasers often are more interested in these other factors than in the instrument's performance. That also means, however, that some brands may be rated a little higher or lower than they would be if rated on musical performance alone. In a few cases I've made small adjustments where I felt that the market seriously under- or overvalued a brand, but for the most part I've kept to describing the market rather than judging the brands.
As can be expected, the upper-level consumer-grade pianos generally have premium components and better performance and quality control than the lower-level instruments. In fact, as mentioned earlier, some may even compare favorably to intermediate-grade instruments, and may be less expensive, too. The entry-level models are basic, no-frills pianos suitable for beginners and casual users, but which a conscientious student may outgrow in a few years. The mid-range pianos usually have better design, performance, quality control, track record, and/or components than the entry-level ones, but not as good as the upper-level ones. As piano quality in general improves, the distinction between levels becomes more subtle and difficult to discern.