Though having such a low version, I am using the module in production on my own servers now. I am sure one or another bug will appear but those will be only detected by testing :-). Maybe I also have to change the interface, so probably my old examples will be no longer working. The next steps will be the documentation and a first Debian package.
Anyway, this module does not only help to develop new classes with puppet, but also finds some mistakes that became forgotten. I intentionally avoided to automatically configure members of a new hostgroup in addition to the nagios services that I am going to test. So when adding TDC to the apache2 class, suddenly Nagios reported lots of unknown hosts. In this case I simply forgot to add them to the corresponding hostgroup for web servers and even forgot to monitor some hosts at all.
It again proves to be true that manually taking care of lists is really prone to errors.