Also, in debian-edu-fai I run cfEngine and use debian-edu-config's
cfEngine ruleset to finalize the system setup.
It makes sense to use cfEngine in a FAI context, because you have all the scripts in a central machine and you run them on other machines to set them up properly. This is what cfEngine was made for. However it does not make sense to download them and to run them on the local machine. In this case bash scripts would be a better alternative (for all practical purposes, bash is readily available almost everywhere).
My opinion is that whoever is not able to write idempotent bash scripts, should not try to automate server configurations (no offence intended). Errors and mistakes are unavoidable, one way or another. The remedy is frequent and systematic testing (automated testing if possible).
Anyway, you have your opinion and I have mine. There is no point in an endless discussion.
Kind regards,
Dashamir