I have both the Airthings Wave+ and the AirGradient Pro. I like them both. The Wave+ can connect to Home Assistant just fine with Bluetooth so there’s no worry about “owning” the data etc. I didn’t care for the initial software that came with the AirGradient but it was easy enough to flash once I understood how ESPHome worked.
With our latest firmware we now natively support Home Assistant and the monitors are auto discovered. So no need to flash ESPHome anymore.
We also expose a local API that makes it very easy to make GET requests to the monitor within your local network and basically gives you all possibilities for easy integration.