i have designed a lot IOT moudules based on Arduino +AIThink or SIMcomm modules such as SIM900, SIM808, but i think this would be the latest version. the ATSAMD21G18 Arduino zero platform get more attractive, the same price as 328+UART, or 32U4， but much powerful.
the Zero A9G GPS tracker features:
1. 3.3V power system~~ very important for mobile/outdoor using, as the lipo batterys can power it directly now,
2. chargeable, on board charge circuits to make the lipo can be charged by USB connector , or Solar panels
3. on boards SD cards, for data logging...