TextMate

TextMate (http://macromates.com) is an macOS X only editor, and there's a TextMate bundle available (https://github.com/masterzen/puppet-textmate-bundle) for editing Puppet manifests. First, install TextMate and Git (available with the command-line developer tools), and follow these commands to set up the Puppet bundle:

$ mkdir ~/temp
$ cd ~/temp
$ git clone https://github.com/masterzen/puppet-textmate-bundle.git Puppet.tmbundle
$ mv ~/temp/Puppet.tmbundle ~/Library/Application\ Support/TextMate/Bundles/
$ rm -fr ~/temp

Now select a manifest and open it with TextMate. In the TextMate dialog, select Puppet and Install Bundle, and you are all ready to rock.