Lancaster University have made the most flexible C/C++ development system for the micro:bit
C++ has full range of use from the control of the LED matrix display to peer-to-peer radio communication and secure Bluetooth Low Energy services. The micro:bit runtime is built on the ARM mbed and Nordic nrf51 platforms.
This is the best way to go for advanced programmers as it supports full use of Bluetooth unlike microPython.
To make a HEX file it uses the Yotta which can be installed on Windows from sourceforge.