Just for reference, it would seem that the Samsung SmartThings hub is becoming a popular consumer-grade Home Automation hub. For better or worse, Samsung is pushing this and it is more open than the soon-to-be-dead Wink hub from Home Depot or the requires-a-monthly-fee Lowe's Iris hub.
SmartThings is not considered to have a great user interface, and until the new version of the hub was entirely Internet/cloud dependent. I have not tested one yet, so I don't know how well the new version, which claims to support offline operation works.
However, for reference, the Smartthings website has a very extensive list of tested/certified devices that are approved for use with the ST hub - both Z-Wave and Zigbee. For a good look at what commonly available Zigbee devices are in the market, I would recommend looking at their site https://www.smartthings.com/compatible-products and clicking on the "Zigbee" sorting category on the left. Very interesting snapshot of current consumer market.
Smarthings also has a developer program with a documented API, so a plug-in that talks to ST hub is also a reasonable possibility.