Puppet and Chef are both popular configuration management tools, but they differ in their approach - Puppet uses a model-driven approach that is easier for sysadmins to learn, while Chef uses a procedural approach in Ruby that provides more power and flexibility but a steeper learning curve. Both tools are cross-platform but Puppet supports more operating systems officially. While Puppet has a larger user community currently, Chef is growing rapidly as well. Their documentation has both improved significantly over time. Pricing models include free open source versions as well as paid versions for Puppet Enterprise and Chef.