There are at least 4 competing IoT connectivity technologies that have already numerous rolled-out products in the market, i.e., RF-433 MHz, WiFi (ESP8266-based devices), Zigbee, and Zwave+. The first two have abundant cheap products, the other two have limited vendor-independent commercial products. I saw a lot of Zigbee & Zwave vendor-locked devices at IoT Expo in Amsterdam last year. Check out full comparison: https://www.iot-now.com/2015/08/10/35653-the-smart-home-radio-protocols-war/.
I spent a short time comparing a WiFi-based and Zwave+-based energy-measuring-capable power socket. WiFi-based chip is compatible with TCP/IP stack so it’s easy to enroll in the network and convert the reading into MQTT message. Meanwhile, Zwave+ has different protocols thus a dedicated gateway is required (I used Aeonlabs Z-stick).
For measuring the power consumption of a dishwasher, the performance of NeoCoolcam Zwave device is not as good as the WiFi product. The reading from the WiFi device is consistent (every 10 sec, customizable set), but the Zwave+ device several times misses the transfer (every 1 minute, fixed set). However, Zwave+ spends so much less power than WiFi which makes Zwave+ a better choice for battery-powered operation.