Thea Flowers of the Winterbloom fame wrote a fantastic article about ADC usage on the SAM D21. This is very well put together blog post including online calculators for different ADC settings. I think this information can also be transferred to other MCU vendors and sets a high bar for embedded hardware blog posts.
P.S. Sorry for so many new forum threads today, but it is just one of those days with a lot of interesting stuff to share.