With respect, Puppet is push-based, not pull-based. Chef is pull-based by default, but you can also use it in a push-oriented manner. Having worked with both

With respect, Puppet is push-based, not pull-based. Chef is pull-based by default, but you can also use it in a push-oriented manner. Having worked with both Chef and Puppet, it is my opinion that Chef is the more scalable of the two, and the one that makes more logical sense to me. YMMV.