I stopped using my R-Pi too. It was free from Adafruit (after a large purchase). I was turned off by the linux distributions (which one is right?) and all the cumbersome overhead code just to do the simplest operations with the I/O pins. The lack of onboard ADCs did it in for me. I use Arduino Due's exclusively. That said, I wouldn't mind using the R-Pi to run the Arduino IDE (Due version) and load programs in the field. Does @Grump_Mike's book have a chapter on this?