Stable Threading +1
BLE API +1
3rd-Party Boron LTE SIM actually working +1
Until those things work AND have a reasonable track record, I will stick to the Electron and Photon. My use case requires threading for viable operation. I use way more data per month than Particle is going to be cost-competitive on. I need to be able to have the end user reconfigure WiFi credentials without physical access. The Photon does not have enough RAM to use MQTT with TLS.
If these things didn’t materialize I would eventually be forced to move to a different embedded platform (likely Amazon’s FreeRTOS port) within a year or so.