After testing the SONOFF S40 Lite in my Zigbee2MQTT/Home Assistant setup, I'm impressed by its plug-and-play simplicity. The compact design (though slightly bulky) doesn't block adjacent outlets, and it paired instantly as a router - no YAML edits needed!

The real magic happened when I used it to extend coverage to distant sensors. While signal strength isn't phenomenal through multiple walls (my coordinator's in a cluttered closet), it noticeably improved my LQI scores. For the price, having both a smart outlet and repeater is fantastic value.

However, I did experience occasional disconnects with blinking green lights - once even triggering a false door alarm when connected sensors dropped. Power outage behavior is disappointing too; unlike Zooz devices, it doesn't remember its previous state after outages.

Compatibility notes: Works seamlessly with SmartThings/Hue hubs (minus HomeKit visibility), but requires hub-specific apps for setup. The rapid red/green indicator lights during operation are annoying if you can't access SONOFF's app to disable them.

Bottom line: A solid budget option for Zigbee networks needing range extension, but power users might want more reliable repeaters like Aquara. Just don't expect flawless performance during network disruptions.