I got a BBQ Guru CyberQ WiFi ATC system for Christmas. I've done 4 cooks with it on my 2 WSMs.
I could not get it to work in Ac-Hoc mode with my Android phone, I had to manually configure it in infrastructure mode.
I did an adapter mod to my WSMs.
I found it works better if I brought the cooker close to the target temperature, within about 25F, before engaging the system.
When I did it this way, the ATC slowly brought the temperature up to my set point, then kept it within +-2F.
When I let the CyberQ bring the temperature up a long way, over 100F, it overshot the target temperature and stayed high for a 1/2 hour.
I have the Pit Viper 10 cfm fan. On both my WSMs, I found the system works best when I set the fan damper about 1/2 open.
The CyberQ WiFi has open lid detection. When the system detects a large, rapid drop in pit temperature, it temporarily disables fan operation. This feature works well. Even with this, after reclosing the lid, the temperature tends to spike. I had to manually intervene on a couple of occasions by closing the top vent for a couple of minutes to let the cooker stabilize.
I used a food probe on one cook, it and the alarm worked well.
I am able to get into it from my LAN and the internet, it sends e-mail alerts, open lid detection, alarms and all the other features work as advertised.
The unit works works well, I am very happy with it.
On the 22 1/2" WSM.
On the 18 1/2" WSM.