Have you ever used it? Reliable enough?
The visualisation with cameras, yes. This is one of the best bang for buck visualisation solutions. 100 clients is the default max. It's HTML5 only, so anything is a client, you don't need to worry about installing java or even a native client. Runs on the PLC.
Only messed around with OpenCV. I guess it is more of a programmers image detection API than an electricians click click go type solution. Still the standard cost in industry for a click click go from say Cognex can be prohibitive.
Logo! is a neat solution but it is artificially restricted. "Oh we need a bit more memory for this application" means moving to S7-1200 and a complete rewrite.
On the Pi reliability, this device is 50 bucks. But it is the most sold computer ever. They have CE certification and a QA department. I would trust a Pi over an off brand "make 1000 PLCs a year" manufacturer for reliability. Chuck a UPS in there and a big enough power supply and you have protected the SD card problem. Then use a read only file system (bit of Linux configuration to do) and you've got a pretty reliable computer.
And if you're programming in CODESYS on there, if they want more reliability, just copy the application to a WAGO PLC, or certain Schneider PLCs and you're set. Copy it to a redundant PLC even.
I think having a range of performance points is crucial to establish yourself in the Home Automation market.
P.S. the PI would only normally be the controller, and you would use remote IO from any of the majors. Perhaps you would use local raspberry IO for cameras or temperature probes, but nothing with long wire runs. That's what industrial is for.