I have the AirThings one. I like it. The biggest drawback is that there is no easy way to automatically record readings, so I do it manually.

I move it from room to room every few days. I was surprised that the upstairs bedroom read as high as the basement (but none are high).

Also, as every website points out, the readings vary quite a bit through the day, and from day to day.

I also noticed that the readings increase when it rains (my current theory is that the low pressure that precedes rain pulls more radon from the ground).

Opening windows helps a lot.