Well - thanks a lot. I've been using Puppet for ages and its really good but I'd never heard of cfengine or chef until now. They are both also in Portage, so now I have to eval. them as well!
Actually I wont bother - but its nice to have a choice ...
When you have a system like Gentoo to worry about, being able to offload stuff with Puppet makes life so much easier. You get the power of choice with Gentoo and the predictability that a thorough Puppet implementation provides.
I have rather a lot of web 'n' email proxies to look after, some of which are well over 5 years old and yet run the latest code without a reinstall or nasty "upgrade". I also have quite a stringent dev -> test -> production process but it works very well and the Gentoo unpredictability snag gets offset nicely.
I even use it to upgrade VMs from x86 to amd64. Which is working OK so far 8)