Admittedly, Puppet's documentation is better than it used to be; I've been using it since 1.x, and it used to be a lot worse. However, it's still a bit tedious to browse through.

The weakest part has always finding reference documentation — that is, things like this [1]. Everything is a bit buried and scattered. At least they finally have a complete list of configuration settings [2] now, which used to be a huge pain.

[1] https://docs.puppet.com/puppet/4.10/types/file.html

[2] https://docs.puppet.com/puppet/4.10/configuration.html

The current version of the Puppet documentation all appears to be for the enterprise product. Our team just evaluated the three and easily found Puppet to have the worst documentation for starting out with the free edition.