I use the Click with CQC (and started the driver for it). I have just purchased my second Click and I am in the process of installing it now. There is a thrid one planned for use with a VSD for an irrigation system. At the price they can't be beat
Highly recommend it for home automation as long as you can integrate it with your HA system. In my case CQC is the glue to tie the PLC to the HVAC, Lights and everything else.
I went down this path because like you I do industrial automation (mainly DCS') and have some 4-20ma loops installed. Using a hack on the M1 automation panel I was able to get them (4-20mA signals) into the system, but the PLC supports 4-20 natively and is better suited to control over the M1 - I will leave the M1 for alarm duties only.
As an example of what they are doing.
The first one is connected to my power meters and counting the kwh pulses and every 15 minutes there is an interval pulse. I totalize these and on CQC calculate the power cost for the last 15 minutes. Because I have solar being sold back to the grid I can tell at the end of the day if I have made any money or not. I can also see when I need to change habits to effect power usage. This PLC also monitors the electric fence alarm, turns a valve on for supplying water to the horses.
I would also consider using one as a weather station, connect the appropriate sensors to it and let it calculate the values and then pass that back to CQC.
The new one will have water tank level, water pressure, hot water tank temp, fire sprinkler valve and all other general monitoring and control not associated with the alarm.
Just ask away if you have any more questions
Mick
Others may not agree - this is a personal preference.