After getting in contact with the NodeMCU DevKit I found different ESP8266 based microcontroller boards. All these boards could re-programmed with the NodeMCU firmware to build a Lua-based IoT node.
The limitation of ESP8266 RAM causes some difficulties with some Lua application programs. You can reduce the memory requirements by intelligent coding. But, this does not help in all situations.
The WifiMCU device based on Cortex-M4 (STM32F411CE clocked with 100 MHz) offers a well known architecture and a lot of peripherals (2 MBytes of SPI flash, 512 KBytes of on-chip flash and 128K bytes of RAM).
These are enough reasons to evaluate this microcontroller for IoT applications.
Based on my experience with the NodeMCU which will be published in the book "IoT node for less then 15 $ - NodeMCU & ESP8266" automn 2015 I describe her the evaluation of WifiMCU.
This GitBook is work in progress and will be enhanced from time to time.