If you mean consumer, off-the-shelf systems, Vera is more reliable than SmartThings in my experience and it works with or without the Internet connection. Vera Edge ($99) is Z-Wave only though (no Zigbee or BT), but soon-to-be-released Vera Plus will have both Zigbee and BT. Vera also provides a way of writing custom plug-ins in Lua language, although it’s a bit more complicated than writing SmartThings “apps”.
There’re also several software solutions that run on PC or Mac worth considering, for example OpenHAB (Windows/Linux/OSX), HomeGenie (Windows/Linux) or Indigo (OSX).