“I've bought several of these (both the lite versions and the ones with the screen). I had trouble with one and performed a WiFi sensitivity test on all of them (six units in total). Two had very low RF sensitivity, to the extent that they were nearly unusable. I contacted M5Stack directly and they confirmed that there was an issue. They have said they will replace the faulty units and stated they would be enhancing their production line tests. That's a 30% fault rate. If WiFi is critical, I would advise you to purchase more than one so you can run a comparison test, else choose another product. The other four units work fine!”
