You just run a command line tool on a node to inspect or create a "system description". You can then export and deploy a description to create repeatable systems. In this regard I think it's similar to what Blueprint[2] does (or did I guess since Blueprint seems dead now). So it's a lot more lightweight tool and has many less features than Puppet, certainly.
Another cool thing is you can use Machinery to build images and deploy to Openstack. Where I work I spent a pretty long time building similar tooling for Xenserver. Sure would have been nice to have just been able to say "oh there's a thing for that". I'm excited to try this tool out and see what it does.
I think Machinery only works on SLES and opensuse right now. I didn't see any mention of other distros.