Best tool: The one that has proper documentation.
Worst tool: The one that doesn't have proper documentation.

God, so much times did I have to waste time trying to read the source code myself, trying to figure out what the fuck was going on because the developer didn't take 2 seconds to document what I had to do...
Or commands that I had to use that exist but I only found out about because I read the source code :|

Documentation most often is outdated, plainly wrong, or non-existing in the first place.
Proper documentation is a pretty rare beast in the wild (okay, Python has it).

But if the tool in question is following keep-it-simple, does only one thing well, features sane defaults, and has a sort-of intuitive user interface (meaning that it fits in the environment where you use it), chances are that it still is the better tool than the well-documented thing that doesn't exhibit that properties.
That is one of the reasons, why every DE maker reinvents all the little GUI tools that make a DE whole without actually being a window manager or compositor.