Best documentation?

Ucglib, a universal TrueColor library for many display controllers for Arduino. Seriously, this thing’s documentation is fucking SICK. They include so many fonts on there, every single one is customizable and every customization is documented.

Worst documentation?

Probably the Objective-C syntax documentation, it’s DIABOLICAL, you have to, first of all, FIND IT. After that, you need to understand the shitty language.