I'd say the AirGradient products are a better choice since they includes VOC, PM and NOx sensors (Aranet4 doesn't), are open source, and Achim Haug who did this

I'd say the AirGradient products are a better choice since they includes VOC, PM and NOx sensors (Aranet4 doesn't), are open source, and Achim Haug who did this study is really dedicated to air quality.