Shimano's XTR 9220 brakes are being reviewed by various outlets, with some focusing on the M9220 model and its 4-piston design. The reviews suggest improvements in consistency and performance, with some outlets noting significant changes and upgrades. However, there is some confusion as reviews also mention other Shimano models, such as the XTR M9200 and XT 8220, making it unclear which specific model is being referenced in each case.