Kargo vs Kops
Kargo runs on bare metal and most clouds, using Ansible as its substrate for provisioning and orchestration. Kops performs the provisioning and orchestration itself, and as such is less flexible in deployment platforms. For people with familiarity with Ansible, existing Ansible deployments or the desire to run a Kubernetes cluster across multiple platforms, Kargo is a good choice. Kops, however, is more tightly integrated with the unique features of the clouds it supports so it could be a better choice if you know that you will only be using one platform for the foreseeable future.
Kargo vs Kubeadm
Kubeadm provides domain Knowledge of Kubernetes clusters' life cycle management, including self-hosted layouts, dynamic discovery services and so on. Had it belong to the new operators world, it would've likely been named a "Kubernetes cluster operator". Kargo however, does generic configuration management tasks from the "OS operators" ansible world, plus some initial K8s clustering (with networking plugins included) and control plane bootstrapping. Kargo strives to adopt kubeadm as a tool in order to consume life cycle management domain knowledge from it and offload generic OS configuration things from it, which hopefully benefits both sides.