KNX is not only the most widely use (in the world, not just Europe) but it is fully decentralized technology so that your installation don't depend on any device whereas Zwave uses nodes (If one node crashes, a whole part of your installation crashes). Also I've heard all the Zwave chips came from the same company. So even if many UNIX lovers go for Zwave, I went KNX. DALI is just for lights and can fit very well with KNX or Zwave. I detest depending on one company alone. That's why I went KNX for my installation. Also, I've found out some professional that knew the KNX, but if I want I can call someone else or learn myself (if I take the time).