The image clarity is satisfactory even in low light conditions. The connectivity is easy for the internal device to communicate with the external one (sound - image OK). However, we were unable to open the Cypriot, so the system is practically useless as when someone rings the bell, we have to go down to open it. The connection instructions are for a different type of electric lock and not the simple Cypriot with 2 wires.
EDIT 21/11/22
With the proper instructions (from where we purchased it), it eventually worked with the classic Cypriot - just after opening it, it takes a few seconds to close again. I reconsider the poor rating as the image and sound are more than satisfactory (even in darkness).