Does anyone use this? I was setting it up a few months ago but it felt very complicated compared to MinIO (or alternatives). Is there a sort of minikube-like tool I could use here?

There's a development/playground deployment for local K8s (e.g. Minikube, KinD): https://github.com/NVIDIA/aistore/tree/main/deploy/dev/k8s.

For production you'd need a proper cluster deployed via Helm, but for trying it out locally that setup is easy to get running.