I'm interested in this too, though I've had mixed experiences in the past using third party HALs for microcontrollers only to discover that they have gaps in API coverage or can only expose the most common use-cases. There was always lot of examples and documentation for the "easy" stuff like GPIOs, timers, ADCs, serial port, etc, but once you got into USB, Ethernet, or RTOS integration then things rapidly got much scarier.
