Both products have the same type of HEPA13 filter, thus addressing the same types of particles. The Compact version is recommended for areas up to 55m², while the larger model, with its bigger filter and fan, is recommended for areas up to 115m².
Both units have the same noise levels at different settings, and both can be controlled via the Mill app in the same way.
Mill Silent Pro Compact do show values of temprature, humidity and particles while the bigger Mill Silent Pro has a more advanced particle sensor, which also measures TVOC in addition to particles, humidity, temperature, and eCO2.