The answer is complicated. If all my home automation devices were switches, I'd use Z-Wave Plus exclusively. As it operates at under 1 GHz frequency, it is better suited for penetrating building materials, and it also has no issues interfering with wi-fi.
But it isn't that simple. Battery devices such as contact and motion sensors tend to be Zigbee, and you have to think about supporting that mesh too with powered devices that repeat. So I went back and replaced some Z-Wave Plus switches with Zigbee in strategic locations.