Simple, rock solid functionality. If you want more, write scripts.
I really like the approach.
Don't ever open that C++ code base unless you have a barf bag.
I started making contributions and gave up because I have better things to do with my time then ruin my soul.
I will also note that they stole the MQTT protocol from Home Assistant - so at least they need ideas from elsewhere. (ie openzwave died so domoticz needs to rely on the same NodeJS subsystem infrastructure of HA)
I love the concept of domoticz - lua, but my god the architecture and implementation is a tire fire.
Is that better or worse than a dumpster fire?
https://github.com/domoticz/domoticz/issues?q=crash
segfault, leak and hang are also fun ones. Apparently the massive memory leaks in the python integration has never been fixed. Not surprising, one look at hardware/plugins/Python*.cpp is bad for your health.
I'm still using it. Upgraded from the C5 to the C7 a few months ago. I use almost entirely Z-wave devices, and the HomeKit integration built into Hubitat makes it easy to manage them all like native HomeKit devices.
Managing probably any Z-wave mesh isn't something I'd recommend for a non-techie, but it doesn't generally requires consistent maintenance. And with Hubitat, it's a small standalone box that does OTA updates.
For me it fills a pretty big gray area between mass market consumer ecosystems and Home Assistant.
Home Assistant is the big one, biggest community, most integrations, you can pay for their cloud stuff to get easy integrations to the big corps above. They also have a dedicated device they sell you can use to run HA.
Domoticz is a bit of an odd bird, I never figured out what was their value propositon
OpenHAB is the one I'd pick if I had to install a system for someone else than myself. It's not exactly easy to configure (the object/entity structure is a bit weird IMO), but it has a pretty decent amount of integrations and it's rock solid German engineering made with boring old Java.
If you want control, my suggestion is to use HA only for the integrations and do all of the brains somewhere else. Either a self-made program that pokes HA using its API or directly via MQTT or Node RED.