Smlight SLZB-06 vs Sonoff Dongle-PZG23

It depends entirely on your protocol. The Smlight SLZB-06 is the more capable device with Ethernet, PoE, Wi-Fi, Zigbee, Thread and a Bluetooth proxy, but it does no Z-Wave. The Sonoff Dongle-PZG23 is a dedicated, well-rated Z-Wave 800 controller, so it wins for anyone whose locks and sensors are Z-Wave.

The radio they carry. The SLZB-06 is a Zigbee 3.0 coordinator (also Thread and Bluetooth proxy) that connects over Ethernet, PoE, Wi-Fi or USB. The Dongle-PZG23 is a USB Z-Wave Series 800 controller only, with no Zigbee, Thread or network connectivity. They cover different smart home devices.

Only the Sonoff Dongle-PZG23. It is built around a Silicon Labs Z-Wave Series 800 chip with S2 security and Z-Wave Long Range. The Smlight SLZB-06 has no Z-Wave radio at all, so you would pair it with a separate controller if you also own Z-Wave gear.

Buy the Smlight SLZB-06 if your smart home runs on Zigbee (and optionally Thread) and you want a network-placed coordinator you can mount centrally over Ethernet or PoE, with a Bluetooth proxy as a bonus. It is the pick when Zigbee coverage and placement freedom matter.

Buy the Sonoff Dongle-PZG23 if you need a dependable, plug-and-play Z-Wave 800 controller for Home Assistant or openHAB, with Long Range and S2 security. It is the affordable, well-rated choice for Z-Wave locks, thermostats and sensors, though it does no Zigbee or Thread.