If all you are controlling is lighting for a few circuits then KNX is probably not for you unless you particularly like the switches.
KNX really comes into a class of its own when you want to do whole building control. Lighting, heating, cooling blinds, BACnet, DALI, DMX, IP etc.
Very proven, very reliable, 150 manufacturers, choice choice choice.

these guys at www.knxshop.co.uk seem to know what they are doing