I've been using the Signals/Billows since they were first launched. Had previously used an Auber which did get the job done but was inconsistant and it took forever to find an acceptable PID.
The Billows works great but I did make one mod for it's attachment. I made a manifold which clips on one of the lower ports. This was necessary for incorporating a sliding gate to control the force of the air. I basically throttle the blower output to about 30%. This permits me to run a very stable and consistant temp with the top vent at 100% open. No proof but I believe the smoke is cleaner with the top vent wide open.
Bottom line... the Billows product is very good and well made. Works as stated. Also, no playing with PID algorithms as with other products. Whats there simply works and I don't think you can change it anyway. Software also works as advertised. The Bluetooth can be quirky at distance, but hey it's bluetooth.