Nabu Casa Home Assistant Connect ZBT-2 vs Sonoff Dongle Lite MG21

For most budget-minded Home Assistant users the Sonoff Dongle Lite MG21 is the better buy: it costs less and can act as a Zigbee router to extend the mesh, not just a coordinator. The Nabu Casa Home Assistant Connect ZBT-2 counters with a higher rating, a stronger antenna and official Home Assistant support.

They are close cousins, both USB Zigbee 3.0 coordinators and Thread border routers with no Z-Wave. The main splits are price (the Dongle Lite is cheaper), the router role (only the Dongle Lite advertises Zigbee router use), and antenna gain (+4.16dBi on the ZBT-2 versus +3dBi on the Dongle Lite).

Yes. Both the Nabu Casa Home Assistant Connect ZBT-2 and the Sonoff Dongle Lite MG21 act as Thread border routers for Matter, though the Dongle Lite ships configured for Zigbee and typically needs a firmware flash to run Thread.

On paper the ZBT-2 has a small edge, with a +4.16dBi antenna against the Dongle Lite's +3dBi. Both use an external antenna and a comparable amplifier, so real-world range is close, and Sonoff bundles a USB extension cable to help placement.

Buy the ZBT-2 if you want the official Nabu Casa radio with the smoothest Home Assistant setup and a slightly stronger antenna, and you are happy to pay a bit more for that polish. It is Zigbee or Thread only, with no Z-Wave.

Buy the Sonoff Dongle Lite MG21 if you want the lowest-cost entry into Zigbee for Home Assistant, or a cheap unit to deploy as a router to extend coverage. Expect to flash firmware if you also want Thread.