Packer (qemu builder) is a huge step up from manually orchestrating image builds with qemu by hand.

Terraform seems to be a fully unique product. No CloudFormation isn't really the same thing, nor are Azure ARM Templates. Terraform has solved multiple problems for me that were not solvable any other way except for lots of manual orchestration done with bash scripts.

I haven't used Nomad yet, but I've heard good things and am happy Kubernetes/Mesos has some competition (no I don't consider Swarm Mode a real competitor yet).